Subject: [NEXTEL-1] Electronics Basics

From: Marcel <[email-masked]>
Date: Tue, 13 May 2003 19:55:36 -0400

Can't figure out what a db is ? Don't understand all this talk about "Filters" take a look
here:
http://www.epanorama.net/links/basics.html

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Electronics basics

Index

Acronyms

Basics

Basic circuits

Measuring

Analogue electronics

Chemistry

Cooling

Digital electronics

Theory

Protecting ideas

Electronics symbols

Component information - changed to own page

Materials

Component markings explained

Electronics construction

Electronics design

Soldering

Component handling

Prototyping

Circuit board design and making

Manufacturing and design

Misc links

Basics

General

Decibelskalan - This table shows voltage levels and corresponding dBV and dBu values. The text on the page is in Swedish but the decibel table is useful without understanding Swedish.

Energy and Electrical Power Tutorials at Howstuffworks

How things work - physical explanations how common things work

How to cheat with dBs ... an intuitive approach - Decibels are relatively simple, yet many engineers seem to have trouble doing the calculations mentally, here are few tips to make them simpler

Metric - English Standard Conversions

SI Units

The Printed Circuit Board Primer - A fine printed circuit board (PCB) is a mixture if high art, and solid engineering. Here is a short primer on what goes into the making of a PCB, the terminology, and the features that enhance reliabity, and lower cost.

The Vacuum Tube Era (1905 - 1948) - electronics history document

Twisted Pair - a site dedicated to those in pursuit of an understanding of Electronics

Unit Conversios

Using a multimeter - A meter is a measuring instrument. An ammeter measures current, a voltmeter measures the potential difference (voltage) between two points, and an ohmmeter measures resistance. A multimeter combines these functions, and possibly some additional ones as well, into a single instrument.

Using the Multimeter to Measure Voltage and Resistance - Multimeters are commonly used to measure voltage and resistance between two points. Current is rarely measured because you must alter the circuit to measure the current.

Acronyms

Abbreviations used in Electronics

Diana's Electronics Info Page - electronics pages aimed at beginners

Electronics Dictionary

Alex's Giant Glossary Listing - a large variety of Glossary and Acronym links pertaining to electricity and electronics

Lexicon of Semiconductor Terms - Intersil has assembled this Lexicon of Semiconductor Terms, Abbreviations and Acronyms to improve understanding of the exciting world of semiconductors.

Metric Prefix in Electronics

What does k, M, m, n and p mean in component markings ?

What's in a dB?

Basic tutorials

Basic electrical laws and circuits analysis techniques - Using Circuit Magic to study electrical circuit theory.

Basic Electronics - online tutorial

Electronics 101 theory course

How Semiconductors Work

Ludovichi - electronics tutorials in French

Silicon, Circuits, and the Digital Revolution - Science Concepts behind High Technology

The Hardware Tutor - a complete beginner's guide to understanding how electronic circuits operate, written from the perspective of a BASIC computer programmer

The Transistor Story - The transistor was probably the most important invention of the 20th Century, and the story behind the invention is one of clashing egos and top secret research.

Williamson Labs Electronics Tutorials

www.electronics-tutorials.com - over 100 individual electronics tutorials

Theory

A Basic Introduction to Filters - active, passive and switched capacitor filters, document in PDF format

Alex's Electronic Resource Library - collection of electronics tutorials

Basic Analog for Digital Designers - tutorial in pdf format

Basics of Electronics - basics of electricity and charge

Cable impedance - what is cable characteristic impedance

Characteristic Impedance of Cable at High and Low Frequencies

Cource notes for power electronics

Electronics Concepts - course on electronics theory

Elements of AC Electricity - Basic Electronics on-line tutorial

Electronics Information Files - pages aimed at beginners, includes simple circuit and some useful free teaching software

Filters - examples of very many different filter types, good page for filter design information

Laws of electronics - Ohm's Law and Kirchhoff's Laws

Ohm's Law - equations, description and examples

Piezoelectricity education - includes basic information, application data, FAQs, introduction to piezo transducers, piezo history and recommended reading list

Power factor - it is more than just cos(Phi)

Practical Analog Design - refresher on op-amps

Semiconductor Physics for Solid State Electronics

The Smith Chart - an RF engineering aid by Phillip Smith of RCA many years ago

Transistors and amplification

Understanding Electricity - an analogy with water

On-line calculators

Capacitance-Frequency-Inductance CALCULATOR - for filter calculations

dbm-Voltage-Impedance CALCULATOR

Resistance-Frequency-Capacitance CALCULATOR - for filter calculations

The Electronics Calculator Website - calculations for basic electronics calculations like resitors, inductors, capacitance and RC constant time

Voltage-Current-Resistance-Power CALCULATOR

Zener Voltage Regulator CALCULATOR

Cooling

Calculation of Temperature Rise of Shrouded Heat Sink

Fahrenheit to Celsius Conversion - This is an useful coversion calculator which converts between Celsius, Fahrenheit and Kelsin degrees

Fan Engineering Information

Spice runs thermal analysis - performing a thermal analysis in Spice allows you to study a circuit's electrical performance and the accompanying thermal effects simultaneously

Thermal resistance: an oxymoron?

Analogue electronics

Analogue electronics handles fixed and changing electroonics voltages and currents.
The real world is an analogue domain and whenever a digital system wants to communicate with it, analogue electronics will almost always be involved. So you need to understand it.

Digital Signal Processors (DSPs) have taken nowadays over many tasks that used to be handled solely by analogue circuits. There are, however, some jobs that are still way beyond the capabilities of digital systems:
high frequency filtering, signal amplification, power amplification, signal switching and anti-aliasing filtering.

Electronics

Electrically Induced Damage to Standard Linear Integrated Circuits: The Most Common Causes and the Associated Fixes to Prevent Reoccurrence - application note in pdf format

Signal level controlling

Gain control goes silicon - ICs are replacing mechanical potentiometers for gain control, providing both flexibility and compactness

Inverted bipolar transistor doubles as a signal clamp - shows the bipolar-inverted-clamp circuit and a typical transfer function

Operational Amplifiers by Oliver King - basic introduction to opamps

Filters

A Basic Introduction to Filters: Active, Passive and Switched-Capacitor - introductory application note in pdf format

Component Pre-Distortion for Sallen-Key filters - application note in pdf format

Introducing the MF10: A Versatile Monolothic Active Filter Building Block- appliacation note in pdf format

Low-Sensitivity, Lowpass Filter Design - application note in pdf format

Negatrons enrich filter, oscillator designs - a test wave of high-performance op amps allows you to incorporate "negatrons" (synthesized negative resistors) into your oscillators and filters

Switched-Capacitor IC Forms Notch Filter

Design articles

Fully differential amplifiers remove noise from common-mode signals - The proper use of differential amplifiers makes it easy to implement differential signaling.

Passive differentiator tops active designs - with properly selected components, this simple passive differentiator can beat the performance of an op-amp differentiator

Step-by-step procedures help you solve Spice convergence problems - iterative approach for arriving at answers to nonlinear problems doesn't always converge on a solution but here are some tips to get results more often

Spice subcircuit simulates any second-order filter

Take account of errors in designs using analog switches and multiplexers - consider nonideal characteristics when you design high-precision systems

Transient test correctly models nonlinear parts - for large signal phenomena nalysis use a frequency-swept sinusoidal source as an input during Spice's transient analysis

Understand capacitor soakage to optimize analog systems - Dielectric absorption can cause subtle errors in analog applications

Digital electronics

Digital electronics handles digital signals. This means that in digital
system the signals can be either logic 0 or logic 1.
In digital circuits different voltage or current levels are used to
represent the logc 0 and logic 1 levels. The used voltage or current
values depend on the logic system used (logic IC family and operating
voltage generally).

Basics

Asymmetrical noise margins - details on interfacing digital ICs

Doing it Digital - Why then, do hobbyists (and small businesses!) often shy away from digital techniques?

Introduction to Boolean Algebra - check also Basic Boolean Algebra Manipulation

Introductory Digital Electronics - on-line tutorial

Leroys Engineering Web Site Logic Design Information

Some logic circuits using discrete components

State Machine Analysis

Digital IC characteristics

About the differences between the TTL families - General characteristics of the TTL families (HC, HCT*, LS*...)

ECL - Emitter Coupled Logic - A quick definition for general consumption

Integrated Circuits and Timing

Low Power Schottky TTL logic levels

Standard TTL logic levels

Understanding Computers - introduces signed and unsigned binary numbers, two's complements, the carry, borrow, and overflow flags, and the effect of shifting signed and unsigned values, article is in pdf format

Memory

How Memory Works

ASICs

Technology articles

Applying basic grounding principles keeps demons at bay - proper grounding and shielding techniques haven't changed much recently, but they've become more critical to a high-quality design

EDA tools let you track and control CMOS power dissipation - knowing where your chip is dissipating power is important for both IC and chip-based system design and proper tools and design techniques can help you analyze power consumption and make the right design decisions

Field-programmable devices - field-programmable devices come in a variety of fruity flavors, and more are arriving all the time

FIFO memories supply the glue for high-speed systems - designers have long used FIFO memories to couple subsystems with disparate data-transfer rates

General Comparison of Programmable Logic Architectures - CPLDs vs. FPGAs

Keep metastability from killing your digital design - synchronizing asynchronous signals causes metastability, which makes it difficult to iron out the bugs during system test

Logic Family Voltage Translation - how to translate between TTL, 74xx, CMOS, ECL, PECL, Low Voltage TTL, LVTTL, etc.

More pins and less space beget new IC packaging - new kinds of IC packages and new ways of connecting to dice-innovations that will profoundly affect upcoming product designs

Moving Data across Asynchronous Clock Boundaries - Reduce data validity and timing problems without reducing data rates through careful design at the interface

Noise budgets help maintain signal integrity in low-voltage systems - peaceful coexistence of CMOS and low-voltage I/O logic, such as 1.5V GTL, requires system designers to pay close attention to noise budgets

S-88.110 DIGISKITTI - notes and information on a kit to help to learn basic digital circuit operation by building your own circuits, text in Finnish

Some designs send mixed signals - phrase "mixed signal" typically refers to designs containing both analog and digital functions or components, but in the real world, every electronic component behaves in an analog fashion, but you can connect these components to form functions amenable to digital approximations

Straightforward techniques cut jitter in PLL-based clock drivers - this article describes jitter and its causes and effects and shows you how to reduce it

To be or not to be asynchronous; that is the question - asynchronous logic conveys advantages in certain situations, but, unlike synchronous logic, which you can typically view as a series of sequential actions, you generally must view asynchronous logic concurrently

Whose fault is it anyway? An introduction to digital fault simulation

Digital chip design

Basic Transistor Level Schematics and Advanced Transistor Level Schematics - describes how digitalcircuits are built using transistors

Layout Design: An introduction to CMOS layout design - Digital Electronics, Boolean Algebra, Transistor Level Schematics, and Stick Diagrams

High speed digital design

When designing high speed digital systems, you need to understand much more than just bits.
According to the classical view, the days when you could ignore signal integrity issued ended when bus-clock rates passed approximately 50 MHz.
At that point, give or take a few megahertz, when you designed buses or interconnects, you had to start taking terminations seriously and stop thinking of reflections as just a little overshoot and ringing on waveform edges at state changes.

Because of fundamentally analog SI (signal-integrity) issues that accompany today's higher data / signal rates, digital electronics is now as much analog as it is digital.
There are only two kinds of electronics engineers working on this field: those who have had SI problems and those who will.

Ideally, all high-speed-logic designs should include tightly coupled bypass capacitors for each IC, and all multilayer pc boards should have power and ground distribution planes. Unfortunately, poor design practices still exist, such as using just one bypass capacitor at the power entrance to a logic board and routing power and ground to the ICs from opposite sides of the board. This faulty distribution scheme creates large spikes on the logic supply voltage and produces significant electromagnetic fields around the board and unstable power for the ICs in the board.

High system speeds are making clock design a critical problem: Clock signals distributed within a printed-circuit board andaround a system must be clean, stable, synchronized, and have as near toa 50:50 duty cycle as possible.

Beware of analog effects in pc-board conductors of fast digital systems - to avoid crosstalk and reflection problems in high-speed digital systems, you must consider transmission-line effects in the pc-board traces

Both-ends termination - Terminations exist to control ringing (sometimes called overshoot or resonance). The best ways to control ringing on very long transmission lines are source termination, end termination, and both-ends termination. The both-ends termination is supremely tolerant of imperfections within the transmission system and within the terminators themselves.

Breaking up a pair - The two traces comprising a differential pair, when routed close together, share a certain amount of cross-coupling, what happens when pair is breaking up

Characteristic impedance of lossy line - This article illustrates the relative influence of skin-effect and dielectric losses on the characteristic impedance of a lossy transmission line.

Choose termination and topology to maximize signal integrity and timing - termination techniques improve noise margins and reduce signal reflections, but they require that you balance trade-offs among conflicting goals

Clock-jitter propagation

Crosstalk, The Practical Way - Crosstalk introduced by neighboring nets, it’s noisiness caused by signals from one net being coupled into other nets. Crosstalk can cause a quiescent (static) clock or data line to cross a logic threshold when a neighboring net switches and create timing violations, false clocking, and intermittent data faults. There are several ways to prevent crosstalk on printed circuit boards.

Differential-to-common-mode conversion - Any unbalanced circuit element within an otherwise well-balanced transmission channel creates a region of partial coupling between the differential and common modes of transmission at that point. The coupling can translate part of a perfectly good differential signal into a common-mode signal, or vice versa. Such differential-to-common-mode-conversion problems frequently arise in the design of LAN adapters.

Driving two loads

Ground Bouche in 8-Bit High Speed Logic - pdf file

Ground Bounce in CMOS Devices - The high edge speeds and clock frequencies of advanced CMOS technology can produce unwanted oscillations during logic level transitions resulting in random logic bit errors.

Grounding Rules for High Speed Circuits - This is an application note document from Analog Devices.

Really cool bus

Decoupling capacitors: use them or fail

Delivering the High-Speed Clock: It's Not Easy To Be On Time - digital system clock in high-speed processors, being late--or even being early--causes serious system problems

Design and layout rules eliminate noise coupling in communication systems - high-speed telecommunication and data-communication schemes, such as SONET/SDH networks, noisy high-speed digital logic often shares board space with sensitive analog circuitry

Designing for minimal jitter when using clock buffers - High-speed digital boards leave little room for timing margin, certainly not enough to take jitter performance for granted. Awareness of just a few key factors can yield superior performance by design.

Designing with PECL (ECL at +5.0V) - application note

Differential receivers tolerate high-frequency losses - If you instead select a differential receiver and a differential cabling system, the receiver thresholds more nearly center in the middle of the data pattern, because differential receivers are commonly specified with more accurate switching thresholds than ordinary single-ended logic.

Differential signaling

Don't let rules of thumb set decoupling-capacitor values

Equalizing cables - basics of designing cable equalizers

Exploit the potential of high-performance CMOS by selecting best interface - high-speed-bus and point-to-point interfaces between CMOS ASICs are no longer limited to conventional CMOS-level signals

Ground-current control enhances dynamic range in high-speed circuits

Growing your own IC clock tree - defining the clock-distribution network is one of the most difficult aspects of high-speed digital systems and system-on-a-chip designs

High-speed connectors' electrical properties eclipse mechanical traits - faster rise times and wider buses have changed all the old rules of thumb, now you must rigorously analyze connectors

High-speed-connector systems - in high-speed systems, you can't afford to look at connectors as just blobs of plastic and pins

High-Speed Digital Design - site with lots of very good high speed design information

How to make a processor with the delay between instructions less than a half nano second in standard 1u CMOS. (GHz instruction frequence)

Minimize Ringing - introduction to high speed chip interconnections and their termination

Modeling and simulation capabilities smooth signal-integrity problems - like speed bumps on a road, signal distortion, crosstalk, interconnect delay, and EMI can force you to slow your logic circuits unless you take steps to avoid these problems early in the design cycle

Modeling skin effect - Why does high-frequency current flow only on the outer surface of a wire or a printed-circuit trace? Magnetic fields cause the behavior you describe. The technical name for this property is the skin effect . It happens in all conductors.

Mysterious ground - For single-ended measurements, don't depend on mysterious ground connections. Always use a good, short ground connection.

Negative Delay - The rule of causality prohibits the existence of a negative-delay circuit. This article reveals how to make a negative-delay clock repeater, which is really just a positive-delay circuit with a delay u set to a little less than one clock period. You can easily implement a negative clock delay by using a coaxial cable of a suitable length.

PC-board layout eases high-speed transmission - As digital techniques move to higher speeds, designers become aware of the need to treat pc-board traces as RF transmission lines. In these lines, you strive to hold the line impedance, Z0, to a constant value typically, and to terminate the line with the same impedance. Data families such as ECL, PECL, and LVDS send data over a pair of traces known as a balanced transmission line. If the traces are on the top of a board with a ground plane under them, then you can model them as coupled "microstrip" lines and if the traces are in a layer with ground planes above and below them, then you can model them as coupled "striplines". This article gives basic design information and dimensions tables for 50 ohm lines.

Practical timing analysis for 100-MHz digital designs - As increasing chip complexity, high clock rates, and analog signal-integrity issues complicate digital design, time-to-market pressures continue to shorten development schedules. These factors present increasing challenges to digital-design engineers. Most technical literature on high-speed design focuses on termination, ringing, and crosstalk. Despite signal integrity's importance, inadequate timing margins cause many more errors in today's 100-MHz digital designs.

Protecting high-speed buses at 1 Gbps and beyond - Circuit-protection trade-offs become more challenging as bit rate increases, but layered protection and new devices minimize the downside.

Reducing Emissions - Many hardware-design engineers use signal-integrity-analysis software to check every trace on their boards for acceptable ringing, crosstalk, and delay. Often during this process, the termination resistors are changed to ensure that the proper voltage waveforms arrive at every receiver. Once the voltage waveforms are acceptable, the design process is complete. This process is good enough for signal integrity, but it's not good enough for EMI because most radiated-emissions problems depend more on signal currents than on signal voltages.

Reducing EMI with differential signaling - Differential signals radiate less than single-ended signals do. That's one of the benefits of differential logic. If the two complementary signals of a differential pair are perfectly balanced, the separation between traces entirely determines the degree of field cancellation. If, however, the two complementary signals are not perfectly balanced, then the degree of attainable field cancellation is limited to a minimum value determined not by the trace spacing, but by the common-mode balance of the differential pair.

Signal-integrity modeling of gigabit backplanes, cables, and connectors using TDR - The TDR (time-domain-reflectometry) method for signal-integrity analysis can help gigabit-system designers produce more accurate interconnect models, resulting in more reliable and higher performance designs.

Signal Integrity: Words of wisdom - Measure everything. Sit with your layout people. Make your hardware testable.

Solving signal-integrity problems in high-speed digital systems - signal-integrity and transmission-line simulation is a crucial part of high-speed digital design

Testing gigabit serial buses: First, get physical - Verifying product designs that incorporate today's superfast interconnects and buses begins with modeling and simulating the physical layer when only components are available to test. And that testing is just the beginning.

The nuts and bolts of signal-integrity analysis

Use local bypass capacitors to meet rigorous high-speed-system demands - when conductors look like inductors and supply lines must absorb amps of fast-edge glitchiness, low-inductance, locally applied bypass capacitors come to the rescue

Why 50 ohms? - Why do most engineers use 50 ohm pc-board transmission lines on circuit boards and why it is a common coaxial cable type?

Digital signal level translations

Circuit converts between TTL and shifted ECL - bidirectional circuit translates TTL to shifted ECL (SECL)

Comparators form 3 to 5V or 5 to 3V translator/transceiver - in some cases it is necessary to interconnect 3 and 5V open-collector transceivers

Interfacing between CML, PECL and LVDS requires level-shift components - information article on different digital signal interfaces interfacing

Low-cost circuit programs EEPROMs - When you migrate to 3.3V system supplies, you must usually replace your old, reliable EEPROM programmer with a new, overly flexible and expensive universal programmer. For less than $100, the circuit extends the functional life of any 5V EEPROM programmer. You can apply the circuit to any bidirectional 5 to 3.3V level-translating application.

Mixed Voltage Systems: Interfacing 3.3 Volt and 5 Volt devices - examples for Xilinx CPLDs and FPGAs

Tapered transitions - Consider the problem of adapting a straddle-mount SMA connector for a 10-Gbps digital application. Exponential transitions are essential at high frequencies. A 1-in. exponential transition from the 0.060-in. SMA signal pad to a 0.010-in. trace should provide startlingly good performance from dc to 10 GHz.

TTL to RS-232 interfacing

Two transistors form bidirectional level translator - illustrates a translation from 5 to 3V, but it can accommodate almost any other voltage levels, provided the logic-low levels are equal (usually 0V), translation from 1 to 100V are possible although slow

Two-transistor circuit replaces IC - Linear Technology's recently introduced LTC4300 chip buffers I2C clock and data lines to and from a hot-swappable card. This task is difficult because the IC must work bidirectionally, meaning that you can simultaneously and actively drive both sides. However, as is sometimes the case, you can replace a complicated circuit by a simple one without much loss of performance. For example, transistors and resistors replace the entire IC. Two npn transistors, connected head-to-head, form the heart of the circuit. The two-transistor circuit offers the additional benefit of acting as a level translator between two logic levels, for example 3.3V and 5V.

Useful Tips Ease Interfacing Of Logic Devices In Mixed 3-V And 5-V Systems.(Technology Information) - There are pitfalls to watch out for when interfacing mixed-voltage systems, this article addresses interfacing logic ICs in 5-V and 3-V systems that use TTL and CMOS switching levels, the concepts discussed can be applied to interfacing other voltage levels as well.

Useful Tips Ease Interfacing Of Logic Devices In Mixed 3-V And 5-V Systems - You Can Insure Data Reliability In Mixed-Voltage Systems If You Pay Attention To These Key Concepts.

Analogue-digital conversion

An analog-to-digital converter (also known as an ADC or an A/D converter) is an electronic circuit that measures a real-world signal
(such as temperature, pressure, acceleration, and speed) and converts it to a digital representation of the signal.
A/D-converter compares the analog input voltage to a known reference voltage and then produces a digital representation of this analog input. The
output of an ADC is a digital binary code. By its nature, an ADC introduces a quantization error. This is simply the information that is
lost, because for a continuous analog signal there are an infinite number of voltages but only a finite number of ADC digital codes.
By increasing the resolution of the ADC, the number of discrete steps is increased, which reduces quantization errors.
Some A/D converters sample the input signal continuously, whereas others sample at specific times. Any A/D converter that uses a
track/hold buffer must periodically connect its track/hold capacitor to the input signal, causing a small inrush current.

All the sampling processes are limited by Nyquist limit.
The Nyquist limit is defined as half of the sampling frequency. The Nyquist limit sets the highest frequency that the system can sample
without frequency aliasing. In a sampled data system, when the input signal of interest is sampled at a rate slower than the Nyquist limit
(fIN > 0.5fSAMPLE), the signal is effectively "folded back" into the Nyquist band, thus appearing to be at a lower frequency than it
actually is. This unwanted signal is indistinguishable from other signals in the desired frequency band (fSAMPLE/2). Usually the signals are prefiltered
before they enter the A/D-converter to avoid too high frequency signal components which can cause this kind of unwanted signals.
In actual practice, you should sample at a rate much higher than two times the Nyquist limit to minimize sampling errors (general rule of thumb is 5 times higher that highest frequency needed to be analyzed well) or you need to provide a very good filter which filters out those "too high" frequency components from your incoming signal.
In some special applications frequency aliasing can also be used in an advantageous manner (generally known as "undersampling" method).

A digital-to-analog converter (also known as a DAC or a D/A converter) is an electronic circuit that converts a digital representation of
a quantity into a discrete analog value. The input to the DAC is typically a digital binary code, and this code, along with a known
reference voltage, results in a voltage or current at the DAC output. The word "discrete" is very important to understand, because a
DAC cannot provide a continuous time output signal; rather, it provides analog "steps." The steps can be lowpass-filtered to obtain a continuous signal.

In D/A conversion process the output of D/A converter is fed through a filter which will remove the image-frequency information (signal higher than 1/2 of sampling frequency) from the output signal. This image-frequency information can distort the output signal.
Two methods exist for removing unwanted image signals from the DAC output to prevent alising in a following ADC. First approach is to use a high-performance lowpass filter (data -> DAC -> high-order lowpass filter). For low pass filtering usually a sixth-order lowpass filter is enough.
The second methos is to use digital-interpolation filters and a simple analogue filter (data -> oversampling digital-interpolation filter -> DAC -> low-order lowpass filter).

1-bit converters

16-bit ADC provides 19-bit resolution - With aid of a programmable amplifier before A/D conversion you can get more relative accuracy to the conversion.

ADC grounding - Chip designers often internally partition the ground-reference net (or substrate) for an ADC into isolated analog and digital regions for good reasons.

Analog to Digital (A/D) and Digital to Analog (D/A) Converters - some basic ways to do them explained

Care and Feeding of the One Bit Digital to Analog Converter - information about one bit digital to analog conversion

DAC IC's: How Many Bits is Enough? - application note in pdf format

Getting the Most from High Resolution D/A Converters - application note in pdf format

Improved amplifier drives differential-input ADCs - ADCs with differential inputs are becoming increasingly popular. This popularity isn't surprising, because differential inputs in the ADC offer several advantages: good common-mode noise rejection, a doubling of the available dynamic range without doubling the supply voltage, and cancellation of even-order harmonics that accrue with a single-ended input. This document shows shows two easy ways to create a differential-input differential-output instrumentation amplifier.

Mixed Signal Circuit Techniques - application note in pdf format

Multiple ADC grounding - If you have a lot of ADCs on the same board and they all tie to the same digital ground, then the various ADC grounds must all be somehow tied together. In a low-resolution, 8-bit system, which needs only about 60 dB of noise rejection, you can use one big, solid ground plane for all the analog channels and the digital logic. In higher resolution systems requiring more noise isolation, you might worry about stray digital currents flowing across the analog-ground region of your pc board.

Overcoming Converter Nonlinearities with Dither - application note in pdf format

The A/D - D/A Laboratory - basics of A/D and D/A conversion explained

The alias theorems: practical undersampling for expert engineers - Aliasing, long considered an undesirable artifact of an insufficiently high sampling rate, is in fact a useful tool for lab testing and analysis.

The beauty of differential drive - Even when sheer chaos is breaking out around an ADC, differential-drive techniques can make the converter perform quietly

Protecting ideas and intellectual property

By 'intellectual property’ we mean intangible legal rights which may be protected by patents, copyrights, trademarks, and trade secrets.
Today in electronics industry a good engineer needs to know documenting and promoting the protection of intellectual property (IP) associated with a given product line.

The major players in the electronics industry realize that to be successful in this business requires that IP be cultivated and harvested in parallel with the technical advances generated by the research and development staff.

There are different protection mechanisms:

Trade Secret: Trade secret can be a formula, pattern, cimpilation, program, device, method, technique or process that derives independent economic value. The information must kept secret, which can be hard.

Copyright: A copyright owner has the exclusive right with respect to the copyrighted work of (a) reproduction, (b) preparation of derivative works, (c) distribution of copies, (d) performance of the work publically, and (e) public display of the work. The rights given to a copyright owner attach on creation or 'fixation’ of the work in a tangible medium. Copyright protection may be appropriate for the expression of ideas such as PLD/FPGA source code, schematics, program listings, etc., it is inappropriate to protect the ideas that these entities embody.

Trademarks: Trademarks are used within our economy to protect consumers from confusion regarding the source, quality, or origin of goods or services. The right given a trademark owner to exclude others who might use marks which tend to confuse the public is a right which is acquired by use of the mark to which protection is sought.

Patents: Patents provide a right of exclusion to prohibit the sale, offer for sale, manufacture, import, or use of a device which is covered by the patent without the permission of the patent holder. While this exclusionary right may be narrowly tailored by the claims in the patent, the goal in any properly written patent is to stake out as broad an area of product coverage as possible. Key to this is a properly written technical description (disclosure) of the invention.

You must understand those different protection mechanism to be able to understand when to use which.

BountyQuest - site for bounty hunters to sort out the good patents from the bad, rewards readers for finding prior art information against listed patents

Dephion Intellectual Property Network - lets you access over 26 years of U.S. Patent & Trademark Office (USPTO) patent descriptions as well as the last 23 years of images, warlier known as IBM Patent Server

Index to Manual of Classification of Patents

Intellectual property: How what you know can hurt you - Many companies unwittingly transfer key technology to rival companies because they are ignorant about how to safeguard their IP.

Ownership of Intellectual Property - In most circumstances, an engineer or software developer is simply not entitled to ownership of the products that he develops on the job

Patent Infringement: The Role of Opinions of Counsel - When the possibility of infringement raises its head, promptly obtaining a competent legal opinion and following it can be a company's best defense

Peter's Patent Page - patent law page, listing of US patent firms and attorneys, patent information, patent searching sites, IP organizations and articles

Protect Your Intellectual Property - You will need to know the types of protection available to protect your intellectual property. This article is an Overview of Intellectual Property Protection for the Electronics Industry. The current trend in the electronics industry is to thrust the engineer into the uncharted waters of documenting and promoting the protection of intellectual property (IP) associated with a given product line. By 'intellectual property’ we mean intangible legal rights which may be protected by patents, copyrights, trademarks, and trade secrets.

The Internet Patents Book - information resource consisting of a collection of informative posts from the news group comp.patents

Electronics symbols

GPL Design Automation Symbol Library - symbol pictures of very many electronics components

Symbols Index for Graphical Symbols - IEC417 electrical symbols, check also new server with search

Electronic Component Template - most common electronics components

Electronic Symbol Libraries - This site contains Electronic Component Symbol Libraries and Electronic Component Mechanical Layout Libraries for AutoCad Version 12. Electronic Symbols are posted for free individual use. The web page has also GIF pictures of the drawings in the libraries.

Popular electronics symbols

Reading Schematic diagrams

Schematic Symbols - A diagram that shows passive components, resistors, capacitors and inductors, and also electrical components such as switches, relays, motors and lamps. Also diagram for active components.

Transistor / Diode / IC (DIP) Outlines

Materials

MAGNETICS® Digital Library. - This literature library can literature files can answer many questions and assist with many magnetic core design challenges.

Component markings explained

A rudimentary resistor identifier - Select colors matching those of the resistor and get the value of the resistor, needs a browser which supports JavaScript

Capacitor color codes - in Finnish

Resistor color codes - text only version, also available in Finnish

Resistor Color Codes

Semiconductor markings explained - what European and Japanise semicondictor component codes mean, also available in Finnish

Surface Mount (SMD) Transistors/Diode FAQ

Transistor Info - transistor markings described

Transistor marking codes

Electronics construction

General information

Beginners/ First-Time Builders tips for electronics circuits

Component handling

ESD Control for Electronics Manufacturing - this application note presents recommendations for establishing basic ESD control equipment and practices in a small to mid-sized manufacturing facility which handles sensitive electronics components and printed circuit boards containing them

Soldering

Soldering is the joining together of two metals to give physical bonding and good electrical conductivity. It is used primarily in electrical and electronic circuitry. Solder is a combination of metals, which are solid at normal room temperatures and become liquid at between 180 and 200°C. Solder bonds well to various metals, and extremely well to copper.

Soldering is a necessary skill you need to learn to succesfully
build electronics circuits. It is the primary way how electronics
components are connected to circuit boards, wires and sometimes directly
to other components.

To solder you need a soldering iron.
A modern basic electrical soldering iron consists of
a heating element, a soldering bit (often called the tip),
a handle and a power cord.
The heating element can be either a resistance wire wound around a ceramic tube, or a thick film resistance element printed onto a ceramic base. The element is then insulated and placed into a metal tube for strength and protection. This is then thermally insulated from the handle.
The heating element of soldering iron usually
reaches temperatures of around 370 to 400°C (higher than needed
to melt the solder).
The soldering bit is a specially shaped piece of copper plated with iron and then usually plated with chrome or iron. The tip planting makes it very resistant to aggressive solders and fluxes.

The strength or power of a soldering iron is usually expressed in Watts. Irons generally used in electronics are typically in the range 12 to 25 Watts.
Higher powered iron will not run hotter,
but it will have more power available to quickly replace heat drained from the iron during soldering.
Most irons are available in a variety of voltages, 12V, 24V, 115V, and 230V are the most popular.
Today most laboratories and repair shops use soldering irons which
operate at 24V (powered by isolation trasfermer supplied with the
soldering iron or by a separate low voltage outlet).
You should always use this low voltage where possible, as it is much safer.
For advanced soldering work (like very tiny very sensitive electronics
components), you will need a soldering iron with a temperature control.
In this type of soldering irons the temperature may be usually set
between 200 degC and 450 degC. Many temperature controlled soldering
irons designed for electronics have a power rating of around 40-50W.
They will heat fast and give enough power for operation, but are
mechanically small (because the temperature controller
stops them from overheating when they are not used).

Soldering iron tips made for electronics work are generally
iron clad coated on copper base. They do wear out with use
(but less than tips made of just copper).
When the iron clad is worn off, you will see the copper inside.
The tip is useable, but not at its peak performance as when t
he iron clad is still on it. The fix is to replace the worn tip.

You will occasionally see gas-powered soldering irons which use butane rather than the mains electrical supply to operate. They have a catalytic element which, once warmed up, continues to glow hot when gas passes over them.
Gas-powered soldering irons are designed for occasional "on the spot" use for quick repairs, rather than for mainstream construction or assembly work.

You need to be careful in soldering because most
electronic components are fragile, and heat sensitive.
Usually our biggest concern is heat. Low enough soldering
temperature and short enough solvering time keeps components
in good shape. Electronics components are designed so that
they can take high temperatures on their contacts/wires for
some time without damage (to withstandard the soldering).
Prolonged exposure to high temperatus will heat up when
inside of the component can cause damage to it.

The solders designed for electronics work are
usually a mixture of tin and lead, designated by two numbers representing the percentages of each metal in that specific mix. The first number always refers to the percentage of tin, the second is the percentage of lead.
Currently, the best commonly available, workable, and safe solder alloy
is 63/37. That is, 63% tin, 37% lead. It is also known as eutectic solder.
Its most desirable characteristic is that its solidus ("pasty") state, and its liquid state occur at the same temperature -- 361 degrees F (around 183 °C).
This is the lowest possible temperature for lead and tin combination to
melt. You will often find "63/37" solder referred to as a quick set solder.
Other commonly used mixture ration is 60/40, (60% tin/40% lead).
Look for solders that are sold as "free of impurities" in the component metals. Impurities cause a "scum" on your solder bead, degrade soldering iron tips, and interfere with the proper soldering.

Nowadays there is tendency to move to use lead free solders, but it
will takes years until they will catch on normal soldering work.
Lead free solders are nowadays available, but they are generally more
expensive and/or harder to work on than tradional solders that have lead
in then.
Depending on the specific mix of metals, lead free will produce differing liquid, solid, and pasty range temperatures. Check with the solder manufacturers for these specifics.

The metals involved are not the only things to consider in a solder. Flux is vital to a good solder joint.
Flux is an aggressive chemical that removes oxides and impurities from the parts to be soldered.
The chemical reactions at the point(s) of connection must take place for the metals to fuse. RMA-type flux (Rosin Mildly Active) is the least corrosive of the readily available materials, and provides an adequate oxide removal.

In electronics a 60/40 fluxed core solder is used. This consists of 60% Lead and 40% Tin, with flux cores added through the length of the solder.

Flux is an integral part of the soldering process to prepare the work surface.

There are certain safety measures which you should keep in mind when soldering. The tin material used in soldering contains dangerous substances like lead (40-60% of typical solderin tins are lead and lead is poisonous). Also the varous from the soldering flux can be dangeroous.
While it is true that lead does not vaporize at the temperatures at which
soldering is typically done,
particulate matter is just as dangerous as fumes would be in terms of
poisoning and there is particulate lead present to some extent in the
fumes from your flux.
Composed of rosin-resin and mixed with an activator (halogen organic agent) that, as the temperature increases, generate noxious components such as salicylic acid and pinene commonly seen as smoke rising from the work area.
High content ratios of resin generate phinol (C6H5OH) and the activators can emit hydrogen chloride (HCL) and other compounds.
The US Government and many other countries have occupational hazard standards controlling the permissible amounts of such compounds in the work area.

When soldering keep the room well ventilated and use a small fan or fume trap.
A proper fume trap or a fan will keep the most pollution away from your face.
Professional electronics workshops use expensive fume extraction
systems to protect their workers (needed for working safety resons).
Those fume extraction devices have a special filter which filters out
the dangerous fumes.
If you can connect a duct to the output from the trap to the outside,
that would be great.

Always wash hands prior to smoking, eating, drinking or going to the bathroom. When you handle soldering tin, your hands will pick up lead, which needs to be washed out from it before it gets to your body.
Do not eat, drink or smoke whilst working with soldering iron.
Do not place cups, glasses or a plate of food near your working area.

Wash also the table sometimes.
As you solder, at times there will be a bit of spitting and sputtering.
If you look you'll see tiny balls of solder that shoot out and can be found on your soldering table.

The soldering iron will last longer with proper care.
Before and during use wipe the bit on a damp sponge. Most bench stands incorporate a sponge for this purpose.
When using a new bit, apply solder to it as it heats up.
Always keep a hot iron in a bench stand, or suspended by the hook, when not in use. Turn of the iron when you do not use it.
Periodically remove the bit and clear away any oxide build up.
Regularly check the mains lead for burns or other damage
(change mais lead if necessary).

Soldering in mass production of electronics devices nowdays use mostly
automated reflow and wave soldering.
It is unconventional to use a hand held iron unless you are doing
board rework.

Reflow is commonly used method for soldering surface mount devices (SMD).
Reflow requires applying a controlled amount of solder and flux to the areas where
connections are to be made. A common technique is to print a pattern of solder paste on the
board, and then put the components onto their places. They tend to stay in position because of
the stickiness of the paste. Optionally, components can be held with chip-bonding epoxy.
When heat is applied, it must produce a time-temperature profile suitable for accomplishing several process steps.
First, solvent evaporation is done at temperatures up to about l00 C. Second, flux reduces
metal oxides as temperature rises to the solder melting point, typically l83 C. Third, as
temperature continues to rise, the solder particles in the paste melt and wetting and wicking
in the joint area begin. In the next step when temperature reaches a peak around 215 C.
The length of time that the work is actually above 200o is usually
limited to one or two minutes to avoid damage. Many plastic encapsulated components can
withstand several minutes of solder-melt temperature when re-flowed.
You can view a reflow oven as just a fancy pizza oven.
It has a conveyor belt and different zones so you can controll the time/temperature profile of the board as the solder starts to flow (tuning this is an art).

There are several techniques for applying the heat needed for re-flow. Two of the most common are infrared and vapor phase.
Infrared heat sources operate at very high temperature
and are placed at the inner walls of the chamber, not in contact with the work.
Organic materials such as epoxy-based boards tend to absorb the IR radiation
and conduct the heat to metal parts which, by themselves, would tend to reflect the IR away.

In the vapor-phase soldering process the vapor surrounding the work is
maintained at the optimum solder-wetting temperature.
This is accomplished by boiling an
inert liquid in a tank. The boiling point is approximately 215oC. When the work is held in the
vapor just above the liquid, the heat at that temperature is transferred to all surfaces quite
uniformly.

In wave soldering molten solder is applied to the bottom side of a circuit board after a preheating
sequence, with cool-down following the soldering. There are variations to the method, mainly characterized by the shape of the solder wave; the choice among them is influenced by the type of assembly and the components being mounted. Solder temperature is typically 260 C.
Wave soldering can sometimes cause micro cracks developing at the leads.
Resistance to this defect is enhanced when moisture is baked out of the plastic material before soldering by either method; 24 hours at 125 C is usually effective.

When soldering SMT components, it is imperative that a component recieves no more than 2 degrees C (about 3 degrees F) a second ramp-up in temperature.
This is to prevent thermal shock and damage to the components. It is OK for a component to be exposed to soldering temperatures, ideally for as little as possible; a few seconds.
If you do thing in other ways, you might get soldering done but you run a risk of damaging sensitive components.
Passive components like SMT resistors, coils, and simple IC's like logic gates generally take the punishment a lot better than film capacitors, PROM's, etc.
SMT reflow ovens, essentially, are identical to the ovens used in Pizza Hut where they stick a pizza in one end and it is taken through heating zones via a conveyor and pops out the other side done. In SMT reflow, the zones are controlled in such a manner that the holy 2 degrees C rule is never broken.
´ost components will stop working at 140C and in the oven they will go over 200C - they will survive, but the PCB should not be powered up until the PCB has cooled to room temperature.

For hand soldering of SMT IC components the following method can be used:
Place the IC on the pads; center it up as well as you can. Using a regular soldering iron, "tack" two opposing corners of the IC to the lands with conventional solder. Don't worry about bridging. Then, apply a small amount of liquid solder flux to one side of the IC, bathing the legs. Then, apply a small bead of solder to the end of you iron and GENTLY wipe this bead across all the legs, from pin one to pin whatever.
You'll see as if by magic that you'll get very few solder bridges. Apply more flux if required. Clean tip of iron completely of solder, and just touch it to solder bridges. The excess solder will "sweat" to the iron. Clean iron tip again and repeat. When done, clean flux with laquer thinner or similar substance. (If you use no-clean flux, you could just be gross and leave it there if you wished, removing excess with a paper towel.)

Using Solder Paste, you can use a hot air gun to place components on a PCB as well.

Some people have also used different kind of ovens for the heating
(for example some people have used old toaster ovens.
When using oven, remeber the following:
Solder paste will only stay reliably sticky for 30 minutes. Make sure that you have your components ready and the oven at the primary temperature before you break the seals on the syringe and start applying paste.
The PCB should be as dry as possible. Before putting on paste/components.
Solder "paste" is made up of finely ground solder held together by flux. Both the solder and the flux are poisenous. An oven used for SMT experiments cannot be used for food preparation afterwards.
Solder paste must be capped and refridgerated when not in use.
The PCB coming out of the oven is very hot and will take several minutes to cool down.
The PCB pads should be "HASL" ("Hot Air Solder Leveled") for best results.

A Glossary of Soldering Terms

ApogeeKits Free Guide to Electronics Soldering - This is a 11 page Acrobat document that introduces how to solder electronics kits and circuits.

An Introduction to Soldering

An introduction to surface mount technology basics

A Study of Lead Free Solder Alloys - This paper highlights lead-free solders and the different combinations of elemental makeups

Building a cost-effective soldering station - If there is one tool which is most important to the DIY hi-fi hobbyist, it is the soldering iron. There are some jobs like soldering where you won't produce a good job without a good tool. This document describes how you can build your own solvering stating usind a Weller 'Magnastat' 24 volt iron with interchangeable tips.

Desoldering - how to remove a component - If you have gotten into the act of building kits, you are inevitably going to face the situation where you need to remove a component that you have soldered on to a pc board. Whatever the case, your desoldering technique can make the difference between a successful effort and a damaged pc board. This guide is for conventional components although some of the steps may be applied to the removal of surface mount components.

Essential Tools - This article details of some of the essential tools you should have in your toolkit if you want to construct electronic circuits or repair electronics devices. The most essential tool is of course the soldering iron, so later in this article there is some guidance on choosing one and some tips on how to master the techniques of soldering.

Everyday Practical Electronics' Basic Soldering Guide - mirrored at http://www.geocities.com/CollegePark/Library/1355/soldering.htm, check also soldering guide photo gallery

Full Glossary of ABCs of SMT

How to mount Chip Components - tips to mount SMD chip components

Have you seen my new soldering Iron? - Information on using a toaster oven to put down fine pitch surface mount parts.

IPC Leadfree Website - information on lead free solders

Lead-free mandate plumbs new design challenges - Initiatives for getting the lead out of electronic products will affect design, debugging, components, testing, and even reliability.

Lead fumes - While it is true that lead does not vaporize at the temperatures at which we work, the soldering fumes are still dangerous.

Learning how to Solder

Making The Right Connection: The Case for Solder

Manual Soldering - Beyond the Basics

PCB Assembly Techniques Course

PCB assembly techniques

Practical Considerations For Attaching Surface-mount Components - What automated soldering methods can be considered for Mini-Circuits surface-mount components? There are two basic methods: reflow and wave soldering.

Practical Surface Mount - ideas on mounting standard components using surface mount methods

Protect Yourself From Solder Fumes

SMT Desoldering Station - Working with SMT is quite difficult without an smt hot air pencil . The prices of SMT soldering/desoldering stations are too high for most home experimenters, so you might consider to build it by your own.

Soldering - short introduction to soldering basics and different solder types

Soldering Surface Mount Chip Components, Point To Point Method

Soldering Techniques - soldering basics introduction to students

Soldering technique reduces pc-board damage - in testing and troubleshooting surface-mounted components, changing parts can be time consuming and easily damage the circuit board

Steps to Better Soldering

The Basic De-soldering Guide Photo Gallery (and Black Museum of Bad Soldering) - De-soldering is required when electronic components need to be removed from a circuit, usually because they are faulty. It may sometimes be necessary during testing or assembly, if a wrong part has been fitted or a modification has to be made. This photo sequence illustrates the basic steps for desoldering a printed circuit board, in order to remove a faulty part.

The Basic Soldering & Desoldering Guide - How to solder, types of iron, desoldering and troubleshooting.

The Basic De-soldering Guide Photo Gallery (and Black Museum of Bad Soldering) - De-soldering is required when electronic components need to be removed from a circuit, usually because they are faulty. This photo sequence illustrates the basic steps for desoldering a printed circuit board, in order to remove a faulty part. Both a desoldering pump as well as desolder braid are illustrated

The Rework & Repair Exchange - open library and forum for the exchange of information relating to soldering issues in the electronics industry

Tips on Soldering

Prototyping

Prototyping electronics devices is a wide topic.
Various protyping techniques are generally needed in electronics
laboratory.
Often used techniques for building electronics device prototypes
are breadboard, wire-wrapping, soldering components to prototyping
boards (like "vero" coppr stip board) or just using point to point
wiring.

Breadboard protypyping is one way to test small circuits easily.
With breadboard you do not need to do any soldering and such.
Breadboards are easy to work with, but they have their limitationsa also.
You can often make stuff work in quite wide frequency range on a plug in
proto board, if you apply some tricks. Just don't expect the
prototype to give much of an indication how the same components will
work on a printed circuit board.

Wirewrapping uses special wire wrapped around square pins.
A wire wrapped connection is made by coiling the wire around the sharp corners of a terminal under mechanical tension. The corners of the pins dig into the wire, forming an airtight joint. This method of connection was developed by Bell Telephone Laboratories, Western Electric Company.
With wire wrapping you can make wire connections to various electronics components without soldering (there are certain limitations to where you can wrap wires to). Wirewrapping is quick and cheap. You can get lots of connections into a very small space.
A distinct advantage of wire wrapping is the ease with which a wire may be removed from a terminal to correct errors or modify wiring. This means that used components are re-usable.
Solid wire is used for wire wrapped connections. Copper is the most commonly used wire.
There are many types of tool available, from a few pounds, up to several hundreds. All usually have some means of stripping the correct length of insulation.
When wrapping, push the wire all the way into the tool and then wrap.
Properly made withstands vibration well. Regular wrap is here quite good.
A modified wrap, where some of the insulation is wrapped around the pin.
is more vibration proof.

One method for prototyping is ratsnesting.
This method involves flattening all ICs legs out, and soldering all the components together so they sit in roughly the same pattern as the circuit diagram.
This is sometimes a bit difficult around ICs since circuit diagrams don't usually draw the boxes of ICs with their pin numbers in their physical locations, but generally in logical positions. However, all resistors, capacitors, transistors, and power rails can be positioned this way. This method makes it very easy to check the circuit out with a meter or oscilloscope, since everything is in its logical position, and reference to the circuit diagram is easy.

One way to build circuits is veroboard.
Is is a circuit biard that has holes and copper tracs on it.
You sintall the component to right places on board,
use the copper traces for wiring and solver everything to place.
Usually you need to cut few copper traces and add some jumber wires.
Veroboard is a good way to build a simple circuit that you want in a hurry.

In some cases other methods are needed.
Nowadays you can buy adhesive copper strips/tape and
conductive ink pens at electronics supliers.
You can buy sheet copper foil with sticky stuff on the back it cuts with an
exacto knife just fine. This kidn of copper sheet or foil
is used as prevent RFI.
Those might be useful for small repairs and changes
on an existing boards, but they are not to recommend for a whole design
work, not even for single prototypes.

Some people have also mentioned technology where you draw th traces
to circuit board with a lead pencil (really graphite).
Then electroplating copper to this.
You need an agitator, a temperature control, Copper Sulfate
and DC voltage (around 1.5V).
Copper will be deposited on one lead or another.
It takes long time to get enough copper to deposit and without
the temp control and constant agitation.
The copper grows in weird and unpredictable patterns,
but mostly stays near the conductor.
I have not used this myself, but some people claim this works.

Using conductive ink
actually, this harks back to the original PRINTED circuit boards. They
were made with a phenolic insulating board, and conductive inks were
literally 'printed' on using a printing process. So, yes, it can be
done. However, the present thick copper coatings, then etching, make
for a far more reliable circuit. The older, truly printed boards
develop cracks easily if the board flexes or changes temperature very
much.
When they went to the present photo-etched method of making circuit
boards they never changed the terminology. We still usually call them
printed circuit boards, or PC boards, even though they are no longer
printed.

If you are not doing any circuit development, but are just building known-working circuits, and you are going to be doing this quite a lot, then it is strongly suggested that you make your own printed circuits based on those designs.
Once you know the techniques for doing this, it is not nearly so hard as people imagine, and produces the best quality and most reliable circuits.

Can the engineer in a garage still "make it"? - can you still make high tech devices in your garage ?

Construction Ideas - This document gives some ideas for constructing one-of-a-kind creations, where designing and making PCBs often doesn't make sense.

Construction Ideas - For most one-of-a-kind creations, designing and making PCBs often doesn't make sense. This document gives you ideas how to use perf board, laminate board, ground plane substrate, wood substrate and small plastic boxes.

Construction Tips - PCB tips and RF tips

Dead Bug Prototyping for Effects - Some of you are familiar with "dead bug" prototyping - named for the resemblance of a DIP IC flat on its back with its legs in the air to a dead beetle. Dead bug style prototyping is usually only taken for a way to patch in an IC with the wrong pinout, but it can be extended to other parts as well.

Hints and Tips for prototyping with Surface Mount Devices (SMD)

How to mount Chip Components - tips to mount SMD chip components

How to prepare the Veroboard - This article tells how you can prepare a veroboard for you electronics project building.

Lämpömittarin kotelo - Information how to make nice front panel to a box. This plans uses the front panel graphics printed to a paper which is then laminated to the case. The text in this document is in Finnish.

Mounting and Handling of Semiconductor Devices - application note from Teccor, pdf file

Opamp Design and Test Board - simple circuit board to make testing and prototyping opamp circuits easier

PCB Assembly Techniques - techniques for student projects and prototyping, e-mail course

SMT Tips from Julie S. Porter - SMT soldering is a lot like jewelry work. For hand work use separate flux. Flatten the solder and cut it into little chips. Get a good bench magnifier. Also get two sets of tweezers.

The Technology of Wire Wrapping - A wire wrapped connection is made by coiling the wire around the sharp corners of a terminal under mechanical tension. This method of connection was developed by Bell Telephone Laboratories, Western Electric Company.

The Breadboard - useful prototyping tool

UHF Construction Precautions - If you are building a kit or circuit that operates at VHF (over 30 MHz) or UHF (over 300 MHz) you should be made aware of proper wiring and construction practices. This is largely experience combined with a good theoretical understanding.

Wire Wrapping

Wire Wrapping Tools Introduction

Casing prototype circuits

Many different types of electrical and electronic devices are both electrically-insulated and protected from the outside environment (heat, moisture, touching, etc.) by putting them to a case. Most cases are made of plastic or metal.

Electronics modules made for very demanding environments (like car electronics) are protected by potting them inside polymeric resins such as acrylics, silicone and urethane. This potting encapsulation is usually done using two-part reactive resins which are mixed then used. Encapsulation involves submerging an assembly into resin (usually epoxy) and allowing the resin to harden.
Epoxy potting protects circuit very well. The obvious disadvantage to having circuits potted in epoxy is that they cannot easily be repaired, as the components are inaccessible through the hard potting material. It also works effectively in maintaining the security of the board design.

Building Replicas of Vox Cabinets and Heads

Crackle Painting Effects Boxes (or anything else!) - one idea for a nice looking speacial painting for metal boxes

Effects Wiring Block - A wooden block with holes drilled can be used to fasten the connectors and controls plus the circuit board.

Encapsulation / Potting - Encapsulation provides effective dielectric resistance and environmental protection while acting as an insulator against shock and vibration. It also works effectively in maintaining the security of the board design.

Fast and easy way for making sexy panels - use computer and ink jet printer for nice front panels

FREE Clock Case Plans - This is a 13 page blueprint document you may download FREE of charge, and print on standard size-A (8 ½ x 11) printer paper. The blueprints provide a detailed materials list and dimensional drawings of each part of the case enclosure. This case will enclose the digital clock kit keeping the user safe from internal voltages. Strain relief for the AC line cord is provided and an isolated back-up battery compartment holds the battery separate from internal clock circuitry for safe easy access by the user.

Introduction to ARP submodules Encapsulation Schemes - Early encapsulated circuit blocks typically consisted of a small circuit board enclosed in a plastic case filled with epoxy potting compound. Some modules filled with silicone rubber so that the circuit board and components were covered, then sealed with a layer of epoxy, to make them somehow repairable.

Links to learning resources for metalworking

Really Quick and Easy Boxes - Many plastic boxes are not strong enough for heavy touring use, and being non-conductive, they will not shield against hum. To avoid humming all you really need to do is to make the box conductive somehow. This document describes ho to do that.

Circuit board design and making

Most copper-clad circuit boards are composed of one or more layers of
fiberglass or other fibers woven or compressed and then impregnated with an
epoxy. The glass fibers (sometimes called E-glass or silica-glass) are
treated chemically in a process called silaning (or silane processing) to
improve adhesion to the epoxy.
FR-4 resin systems are generally green, whereas G-10 is usually tan. The
boards are made of woven fiberglass (also called E-glass or silica glass),
which is treated chemically to adhere to the epoxy resin.
So the materials used in those circuit boards are the fiberglass,
epoxy and copper.
The typical thickness of the copper on the circuit board is
35 micrometers and 17-18 micrometers.

One of the things that scares people away from doing there own electronics circuits is the fabrication of the circuit board.
A custom etched board makes things easy to put together and minimizes wire lengths.

This section of web page describes how you can design and manufacture your own printed circuit boards (PCBs). There are many techniques for making PCBs, some of them are more suitable for low volume manufacturing and other are better for high volume manufacturing in factories.

PCBs are great when mass-producing a device or when the circuit complexity makes point-to-point wiring impractical.

Please note that making these PCBs involves some potentialy hazardous chemicals and tools. It is your own resposibility to take suitable precautionary actions! If you do not know what these suitable precautionary actions are, DO NOT use these chemicals and tools. I recommend wearing protective goggles, clothing, and chemical resistant gloves all the time when handling these chemicals, tools and PCBs!. In some countries the use of some of the tools and chemicals may be bound to restrictions, such as proper waste disposal and licenses, or may even be forbidden. For example both NaOH (caustic soda) and Iron Cloride are very unhealthy if used carelessly.

General

EverythingPCB - web site on PCB making information links

Forming The Conductor Pattern to PCB - how it is done

Making of Your Own PCB - short instructions for basic circuit board making process

The Printed Circuit Board Primer - A fine printed circuit board (PCB) is a mixture if high art, and solid engineering. Here is a short primer on what goes into the making of a PCB, the terminology, and the features that enhance reliabity, and lower cost.

Designing info

There are many things which should be considered when desiging electronics circuit boards.

Drill size is generally selected to be slightly larger than pin diameter,
and pad size larger than this (large neough to be well soldered).
If using plated holes, drill size must be enough larger than pin to
allow for thickness of plating. Consult your PCB service for their
standard drill sizes to avoid "special drill" charge.
Generally the drill size should be at least 20% bigger than the pin diameter,
to allow for tolerances and reduction in dia from plating.
The restring should be 25% of the drill, with a minimum of 12mil and a max
of 24mil or so according to your design rules. Pad diameter = drill +
2*restring.

All manufacturers will have a recommended pad to hole ratio spec. This
is typically 1.8, so the pad should be 1.8 times larger than your hole
size to allow for any drilling offset errors and plating.
Some say your pad should be at least double the hole size. You can go
less than this if you need to (check with your manufacturer), but it's
a nice rule of thumb.

Drill sizes are most often specified in "finished" hole diameter which
includes the plating through the hole. So if you specify a 0.8mm hole
then thats what you should get, but manufacturers vary on this and it
can be a big potential problem, so check with them first. Typically
specify your hole at least 0.1mm extra over the pin size you will be
using. Don't try and get a 0.8mm pin into a 0.8mm hole.
If a pin is a square in section, the drill size has to be 1.41 larger
than the side length of the square.

For general purpose axial components like normal
resistors and capacitors and also IC's,
0.8mm Hole (around 32 thou = 0.032") and
1.75mm or 2mm pad size are generally good choises.
This is a reaonable minimum size if you have enough space.
Really there is no disadvangate to use larger pad size
(uless you go to a very hige side), and they are much easier to work
with at hand soldering.

For some components such as power diodes or Transistors you will need
to use 1mm or 1.2mm holes.
When selecting most suitable hole size,
look at the spec for the device leg diameter, plus it's tolerance.
Then look at the tolerance in your specifications for a finished hole size.
Your drill hole needs to be okay, if a worst case scenario occurs and you
have a component leg on the top tolerance, and a drill hole on the bottom
tolerance.

If you are using a plated through hole then the PCB manuafacturer is going
to drill that hole above your stated size, so that it plates down to your
required size. Generally, a manufacturer will either go 0.15 mm above your
stated hole size, or 0.05 mm above your top tolerance. When they do this,
your pad needs to be sufficently large enough. This is called the annular
ring. For general purpose designs, at standard PCB manufacturers, aim for
an 8 thou (0.008") annular ring. If your working on cutting edge stuff and/or use a
very good PCB manufacturer you could design to a 5 thou (0.005") annular ring.

It is a good idea to design PCB's using imperial measure, because the vast
majority of components are based on 0.1" pitch or other imperial
measure. A 2mm pad is 80 thousands of an inch.

Normally the PCB design software offers the possibility of AUTO DIAMETER of
Pads/Vias. It means, you have to specify the Drill (Hole) size only, the
rest will be set by software.

When putting traces and pads to circuit board, you need also keep
in mind the separation of different PADs.
You need to allow at least 1mm/KV (1inch/27KV)
air gap between pads/traces at all times, for traces at different
potentials, to prevent arcing. This is the minimum.
In many cases in safety critical applications, there are safety
standards which give very detailed information of needed safety
distances (those depend on safety level and environment).

There are also other circuit board design considerations, especially on high speed electronics.
Ideally, all high-speed-logic designs should include tightly coupled bypass capacitors for each IC, and all multilayer pc boards should have power and ground distribution planes. Unfortunately, poor design practices still exist, such as using just one bypass capacitor at the power entrance to a logic board and routing power and ground to the ICs from opposite sides of the board. This faulty distribution scheme creates large spikes on the logic supply voltage and produces significant electromagnetic fields around the board and unstable power for the ICs in the board.

Crosstalk, The Practical Way - Crosstalk introduced by neighboring nets, it’s noisiness caused by signals from one net being coupled into other nets. Crosstalk can cause a quiescent (static) clock or data line to cross a logic threshold when a neighboring net switches and create timing violations, false clocking, and intermittent data faults. There are several ways to prevent crosstalk on printed circuit boards.

Designer's Den PCB Designer's Page - useful PCB designing information

Electromagnetic theory imposes constraints on pc-board design - an understanding of electromagnetic effects often leads to a better pc-board design than prototyping and debugging in the lab using traditional rules of thumb

Glossary of Printed Circuit Design and Manufacturing - A collection of words with their meanings. This glossary contains only meanings which apply to PCB design and manufacturing, with rudimentary electronics.

Keep pc design from torpedoing in-system programmability - pc-board design can make or break an application of in-circuit programmability

New printed-wiring-board materials guard against garbled gigabits - old standby FR4 circuit board material can produce unacceptable signal distortion at gigabit speeds, several new materials promise improvement on this

PC-board layout eases high-speed transmission - As digital techniques move to higher speeds, designers become aware of the need to treat pc-board traces as RF transmission lines. In these lines, you strive to hold the line impedance, Z0, to a constant value typically, and to terminate the line with the same impedance. Data families such as ECL, PECL, and LVDS send data over a pair of traces known as a balanced transmission line. If the traces are on the top of a board with a ground plane under them, then you can model them as coupled "microstrip" lines and if the traces are in a layer with ground planes above and below them, then you can model them as coupled "striplines". This article gives basic design information and dimensions tables for 50 ohm lines.

PCB making tips á la George Patrick - reference to information about printed circuit board design

PCB maximum trace current - The graph in this page shows the maximum printed circuit board (PCB) current for given trace widths. The graph shows information for both 1-ounce and 2-ounce copper traces. Outside layers of PCBs are generally available in 1-ounce and 2-ounce copper, a reference to the weight of the copper per square foot of board. Inner layers of multilayer boards can have 1/2-ounce copper. One-ounce copper is nominally 1.3435 mils or 0.0013435 inch thick. Good design practice limits temperature rise on FR4 board to 20°C (MIL-STD-275C).

PCB Trace Impedance Calculator - Calculates the characteristic impedance and per-unit-length parameters of typical printed circuit board trace geometries. The source for formulas used in this calculator (except where otherwise noted) is:
IPC-D-317A, Design Guidelines for Electronic Packaging Utilizing High-Speed Techniques, Jan 1995; Section 5, pp. 13 - 36.

PCB Trace Width Calculator - This web calculator calculates the trace width for printed circuit boards based on a curve fit to IPC-D-275.

RF and Microwave Basics Impact PCB Design

SMT Footprints - There are many sources of footprint info. The most reliable is the IPC-SM-782, "Surface Mount Design and Land Pattern Standard";. However this doesn't cover all SMT components. Often a components Data Sheet will have a footprint, but these should be used with caution.

The Institute for Interconnecting and Packaging Electronic Circuits (IPC) - a trade association representing over 2300 companies in the electronic interconnection industry worldwide

Tips For Making PC Boards - a few general rules of thumb that can be used when laying out PC boards

Trace-dimension control reduces crosstalk

Why 50 ohms? - Why do most engineers use 50W pc-board transmission lines on circuit boards

General PCB manufacturing

A Home Photoetching Operation - Information on circuit board making and how to make a nice etching tank.

Etching Circuit Boards Using Cupric Chloride and Acid Solution - This page gives a nice description of maintaining a cupric chloride etch bath. This page has also information about etchant disposal.

Green CirKit® Reference Stack - instructions how to make circuit boards, also PC software for designing

How to make really really good homemade PCBs - with the methods described, you can produce repeatably good single and double-sided PCBs for through-hole and surface mount designs with track densities of 40-50 tracks per inch and 0.5mm SM pitches

Low volume (hobby) manufacture of double sided Printed Circuit Boards (PCB's) - This document describes how to manufacture the double sided PCBs. Other ways of doing this exist, and this only describes the way I find most efficient in low volume PCB manufacture.

Making PCBs at home - design, making and drilling tips

Pollution Control and Hazardous Materials Minimization in a Printed Wiring Board Shop: A Case Study

The Five Methods Of PCB Fabrication - There are only 5 ways to make a circuit board. This document collection describes them.

Tools

Link to PCB design software on the web

PCB Etchant Tank - Here are instructions on building a really good PCB etching tank

Using laser printer in circuit board making

How to circuit board using Windows and Laser Printer - check also what equipments you need to do the job

Inexpensive Printed Circuit Boards - article describes a simple and inexpensive approach to fabricating printed circuit boards with your laser printer

Using plotter in circuit board making

Resist Pen Works in HP Plotter - very promising progress report on an attempt to use plotter with special pen for making circuit boards

Electronics design

10 Steps to Better Packaging Comm Infrastructure Designs - Given the rapidly evolving world of communication equipment designs, it's often easy to forget about the nuts and bolts of system packaging. What are the primary issues that need to be considered when packaging electronics for a communication system? Whether it is an IP router, telco switch, or wireless base station many of the design issues are the same.

An introduction to CMOS layout design

Avoid The Common Pitfalls When Designing Boundary-Scan Boards - IEEE 1149.1, or "JTAG," has become one of the mainstream design-for-testability (DFT) techniques and used to provide test coverage for circuit nets that aren't accessible by conventional test probing

BIST means more measurement options for designers

Cable and harness EDA enables advanced electrical-system design - Wiring is so fundamental that we forget that it is a system unto itself.

Calculation of Temperature Rise of Shrouded Heat Sink - an analysis of a large aluminum extruded heatsink with a shroud

Chipcenter Design Tips - many design articles

Choosing a heat sink: some tips and recommendations

Combining standard component values improves circuit designs - Make the most of components by using alternative circuit configurations to approximate ideal response and improve circuit yield.

Design Flow Chart

Designing for reliability: a checklist - building products that stand the test of time requires understanding reliability engineering and mathematics and must also understand reliability prediction and a failure's effect on the user

Designing for Testability - technology, techniques and economics

Designing RC active filters with standard-component values - By modifying filter-design equations to implement exact component values, you can minimize filter-response distortion and statistically predict behavior.

Electronic Prototyping: Tips and Pitfalls - This page will discuss electronic prototyping and construction methods. Many documents accessed through this page are taken from postings on the Usenet newsgroup "sci.electronics".

EMI and circuit components: where the rubber meets the road - You need to know how components behave in the real world and what their limitations mean in terms of EMI. Some guidelines in proper component selection for EMI and in designing simple EMI filters will help in the battle.

Environmental-stress screening improves electronic-design reliability - Environmental-stress screening is a powerful tool for electronic-systems designers. Environmental-stress screening (ESS) is an essential step in the design cycle of electronic systems, particularly as these systems shrink in size and increase in complexity to satisfy the growing customer need for low-power, portable, high-quality gadgets.
ESS helps you design and develop highly reliable products that will operate in different environments.

High-Speed Digital Design - information site

Hot-swapping signals - Hot-swap designs were Once reserved for medical-support systems, telcomm, or other "high-reliability" installations. now everybody wants to swap with the lights on.

How To Draw Schematic Diagrams - A well-drawn schematic makes it easy to understand how a circuit works and aids in troubleshooting; a poor schematic only creates confusion. By keeping a few rules and suggestions in mind, you can draw a good schematic in no more time than it takes to draw a poor one. In this appendix we dispense advice of three varieties: general principles, rules, and hints.

Keeping embedded system design projects on time and close to budget - An all-too-common mistake in the development of embedded control systems is to rush into the design process with little or no appreciation for the full magnitude of the job, only to find oneself with insufficient time or resources to do the job right.

Knowledge of clocking aids ASIC-emulator choice - Real ASICs and software simulations differ significantly. Though costly, ASIC emulators often help to bridge the gap. Recognizing the trade-offs among emulator-design approaches can point you toward a wise investment.

Lead-free mandate plumbs new design challenges - Initiatives for getting the lead out of electronic products will affect design, debugging, components, testing, and even reliability.

Live Insertion - Many applications require the ability to exchange modules in electronic systems without removing the supply voltage from the module (live insertion). To avoid damaging components, additional circuitry modifications are necessary. This document describes in detail the phenomena that occur during live insertion and presents circuit solutions for potential problems.

Lowpass filter uses only two values - A low number of component values is advantageous for low-cost manufacturing. This composite low-pass filter design uses four inductors of two different values and five capacitors of two different values.

Molded Interconnect Devices Reshape Electromechanical Design - MIDs overcome pc-board limitations, incorporating interconnects and circuitry in plastic housings for easier assembly

Practical Considerations For Attaching Surface-mount Components - application note which briefly describes reflow and wave soldering methods

Predicting Semiconductor Failure Modes - Electrostatic Discharge (ESD) is an invisible destructive force that causes failure of electronic devices and reduces the reliability of electronic systems

Product Usability - How can designers make products that users will find usable?

Programmable analogue ICs challenge Spice-and-breadboard designs - After years of Spice-and-breadboard designing, analogue designers can now take advantage of increasingly sophisticated programmable components and software-configuration tools. But how easy are such components to use, and can they challenge traditional design approaches?

Sense of self: enabling systems to monitor—and control—their environment - There's nothing quite like having to explain to your boss that your entire network is down because a $12 fan died. Proper management of the enclosure environment lets you pre-empt such disastrous and embarrassing failures. The telecomm industry already demands high availability, and if data communications wants to compete for voice and video services, it needs to aim for a similar standard. To achieve efficient high availability, however, you need to monitor a system to identify potential failures before they happen and actively prevent them. Good system monitoring occurs on many levels.

Simplicity pays off in circuit design - in circuit design simpler is often best

Simple design enhancements enable in-system test: part one - Many standard yet proprietary strategies facilitate in-system test. Certain design features and enhancements minimally affect product cost yet significantly expedite validating, manufacturing, and debugging of silicon, thus reducing time to market and field failures.

Simple design enhancements enable in-system test: part two - Many standard yet proprietary strategies facilitate in-system test. Advanced design features and enhancements can minimally affect product cost yet expedite validating, manufacturing, and debugging of silicon, thus reducing time to market and field-failure cost.

Some Like It Cool... - Remote comm equipment now resides in harsh environments, creating heat dissipation problems. Designers must rethink thermal management to beat the elements.

The Design Method - This document is a complete index of design steps of typical electronics device design.

The Owner's Manual as Engineering Spec - Writing the Owner's Manual before beginning design will help you get a better product in less time

The Ultimate CAD Directory by Tenlinks

Useful Design-for-Test Practices - Successful DFT for deep-submicron system-on-a-chip ASIC designs requires attention to detail from specification all the way through tape-out

Understanding Low-Power Designs - Designing low-power digital and analog devices means sometimes getting back to basics.

Use Shielded Electronic Enclosures To Meet EMC Standards - proper selection of shielding options early in the design cycle ensures electromagnetic compatibility without sacrificing other objectives

Web-based Design

Manufacturing

Maximizing the Effectiveness of Your SMD Assemblies

Metal Web News - metalworking info

Safety guidelines for building electronics equipments

Surface Mount Soldering Recommendations - application note from Teccor, pdf file

SMTnet.com - electronics manufacturing information exhange

The Basics of Manufacturing Technology

Basic circuits

Hand Clap Electronic Control - turn relay on and off by hand clap

Intercom

Pine Racecar Victory Judge - simple circuit takes care of lighting the appropriate LED to indicate the winner

Quiz Circuit

Chemistry

Chemical Elements

Periodic Table of Elements

WebElements periodic table (professional edition)

WebElements periodic table Scholar edition

Misc links

Dimensions of the Human Figure - This information is useful for ergonomic design.

Bell Labs Acoustics & Speech Research Heritage Page - list innovations made in famous Bell Labs

Properties of Plastic Materials

www.epanorama.net <[email-masked]>

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