Guide to Mastering Electronics: Contents and Intro

I set out to write this preface as a rationale for the guide, and as an explanation of the reasons why I wrote it this way. I was going to describe the electronics industry and the way it has grown almost beyond recognition in the last couple of decades. I was going to say how the changes in the technology have resulted in changes in the way the subject is-must be-taught. But, well into the third page, I decided not to. Much of it is in the first and the final sections, anyway.

Instead, I will simply (and briefly) explain what I have done. Mastering Electronics is intended as an introduction to the subject for anyone who wants to understand the basics of most areas of electronics. I have tried to make the coverage as broad as possible within the confines of an afford able guide. Most aspects of electronics--from basic semiconductor theory to television and computers--have been fitted in, but with deliberately unequal coverage. In what is intended to be a fairly basic guide, it seems sensible to devote proportionately more space to the more fundamental topics.

On the principle that if a picture is worth a thousand words, a circuit diagram must be worth five thousand, I have been lavish with the illustrations. The concomitant is that the text is, in places, on the dense side and will repay rather careful reading.

I have written the guide in a way that reflects modern thinking and requirements for the electronics technologist, placing an emphasis on systems and on electronics in 'real life' rather than in the laboratory.

Following the structure of most recent syllabuses, I have reduced the number of mathematical descriptions to an absolute minimum, including only such formulae as are essential for calculations. This has saved a certain amount of space, which I have used to put in suggestions for practical circuits and experiments. Wherever I recommend a circuit for practical work, I have built and tested the design before committing it to paper.

Guide to Mastering Electronics can be used as a self-teaching guide or as a textbook; I think that on balance it has probably gained something in being designed for this dual role.

It appears to be usual to use the end of this intro to thank everybody who helped me produce the guide. I think I will apologize instead, to my wife and boys, for a certain degree of preoccupation during the last few months ....

SYMBOLS and UNITS

Successive attempts to 'metricate', both in the UK and in the USA, have left the electronics industry a little confused about units in some areas.

Similarly, different 'standards' have been issued in different countries regarding the symbols to be used in circuit and logic diagrams, and although there are general similarities, there are disagreements about the details.

I have tried to take a middle and sensible course in this Guide. I have used SI metric units for all measurements, except where the original is clearly in Imperial units, imported, paradoxically, from the USA. For example, the plastic DIL pack (dual in-line) for integrated circuits has a standard spacing between connecting pins: it seems silly to assert that the spacing is 2.54 mm, when it is clearly 1/10th an inch! I have used British Standard symbols in all circuit and logic diagrams except where, for reasons of its own, the electronics industry has obstinately refused to use them. In such cases I have bowed to the majority opinion and done what everybody else does. Where symbols are distinctly different, for example

BS 3939: 1985/IEC 617-12: 1983 and ANSI Y32.14: 1973

standard logic symbols, I have shown both and then stuck with the BS/IEC version.

For component values, I have generally omitted the units in circuit diagrams; thus a 1.8 k-Ohm resistor becomes 1.8 k on the diagram. I have avoided the 1k8 convention.

GLOSSARY OF TECHNICAL TERMS AND ABBREVIATIONS

A Ampere (amp); the unit of electric current.

a.c. Alternating current.

AF Audio frequency.

alternating current An electric current that alternates in its direction of flow. The frequency of alternation is given in hertz.

AM Amplitude modulation.

amplitude modulation A system of modulating a carrier in which the amplitude of the carrier is changed in sympathy with the modulating signal.

analog A system in which changing values are represented by a continuously variable electrical signal.

astable A circuit which has no stable condition, and oscillates at a frequency determined by circuit values. See also oscillator.

audio Relating to a system concerned with frequencies within the range of human hearing.

bandwidth The range of frequencies to which a system will respond in the required manner.

base One terminal of a bipolar transistor.

BASIC The most popular computer language for small computers. The letters of the acronym stand for Beginners All-purpose Symbolic Instruction Code.

binary A number system to the base 2.

bipolar transistor A transistor in which current is carried through the semiconductor both by holes and electrons.

bistable A system which can have two stable states, and which can remain in either state indefinitely.

Boolean algebra A system of formal logic used for minimizing complex digital systems.

breakdown A sudden loss of insulation properties, resulting in a rapid and large current flow. Typically, breakdown might occur in a semi conductor device operated at too high a voltage.

bus A group of wires having a related function. Used particularly in computers.

candle Unit of luminous intensity.

capacitor A component used in electronic circuits, exhibiting the property of capacitance.

CdS Cadmium sulphide; used in photoresistors.

chrominance In a television system, the part of the television signal concerned with color.

class A amplifier An amplifier in which the output transistor is operated at approximately half the supply voltage, resulting in a continuous heavy current flow, but low distortion.

class B amplifier An amplifier in which the output is shared between two transistors, resulting in much more efficient operation but potential problems from crossover distortion CMOS Complementary Metal Oxide Semiconductor. A family of digital logic, featuring medium-speed operation, and very low current requirements.

collector One terminal of a bipolar transistor.

conductor A material through which an electric current can flow relatively easily.

conventional current Electric current, regarded as flowing from positive to negative.

CPU Central Processor Unit. The main number-processing and control section of a computer. In a microcomputer the CPU will be a micro processor.

CRT Cathode ray tube.

crystal Usually refers to quartz crystal, used as a precision timing element in many circuits. May refer to a piezoelectric crystal pick-up.

Darlington pair Transistors used in a configuration giving high gain and high input impedance.

dB Decibel: one-tenth of a bel, the unit of relative power. See decibel.

d.c. Direct current.

decibel One-tenth of a bel. A measure of power, on a logarithmic scale.

Symbol dB. The decibel is a convenient unit for representing a very large range of powers.

demodulation The recovery of a modulating signal from a modulated carrier.

denary The 'normal' number system, to the base 10.

diac A bidirectional breakover diode. Often used for triggering a triac.

digital electronics The branch of electronics concerned with the processing of digital systems, usually in binary.

DIL-pack The standard package used for digital integrated circuits, and many analog integrated circuits.

diode A component, either semiconductor or thermionic, that permits current to flow through it in one direction only.

direct current An electric current that flows steadily in one direction (compare alternating current). discrete Used to refer to systems constructed from individual components--e.g. transistors, capacitors, diodes, resistors-as opposed to systems made using integrated circuits.

disk A system of magnetic recording used to store large volumes of information. Used with computers, the disk enables relatively rapid recovery of recorded information, as compared with tapes.

doping The addition of tiny amounts of impurities to semiconductor material during the manufacture of semiconductor devices.

dynamic RAM A Random Access Memory circuit, used in computers, in which information is stored in the form of electric charges. Dynamic RAM must be read at intervals of a few milliseconds if the information is not to be lost. However, dynamic RAM is cheaper than static RAM and can be packed more densely.

emitter One terminal of a bipolar transistor.

EPROM Erasable Programmable Read-Only Memory. A ROM in which data are fixed, but can be erased if required by the application of suitable electrical signals or ultraviolet light.

extrinsic semiconductor A semiconductor material produced artificially by the addition of impurities.

F Farad: the unit of capacitance. See farad.

fan-in The number of standard devices that can be connected to the input of a digital circuit.

fan-out The number of standard devices that can be connected to the output of a digital circuit.

farad Unit of capacitance. The farad is a very large unit, the largest practical unit being the microfarad.

ferrite A finely divided ferrous dust, suspended in a plastic material.

Ferrite has useful magnetic properties, but does not conduct electricity.

fiber-optic A glass or plastic fiber used for the transmission of light over long distances.

field timebase In television, the basic oscillator used to control the vertical scanning of the picture.

field-effect transistor A type of transistor characterized by a very high input resistance.

flip-flop General term for a bistable, astable or monostable circuit.

flux Various meanings, but usually a resin added to solder in order to prevent the formation of oxides on the material being soldered.

FM Frequency modulation.

frequency The number of waves, vibrations or cycles of any periodic phenomenon, per second. Unit hertz.

frequency response Generally the range of frequencies that can be processed by an electronic system.

gain The factor by which the output of a system exceeds the input.

gate (a) A component in digital logic circuits.

(b) One terminal of a field-effect transistor, or other semiconductor device.

Ge Chemical symbol for germanium, a semiconductor.

H Henry: the unit of inductance.

Hall-effect A change in the way that current flows through a conductor or semiconductor when subjected to a magnetic field.

henry Unit of inductance.

hertz The unit of frequency. One hertz equals one cycle per second.

hexadecimal A number system to the base 16-commonly used in computing.

hi-fi High-fidelity-used to apply to audio systems that reproduce the entire audio spectrum, and beyond, with minimal distortion.

Hz Hertz: the unit of frequency.

IC Integrated circuit.

IGFET Insulated Gate Field-Effect Transistor.

impedance The ratio of the voltage applied to a circuit to the current flowing in the circuit. Similar to resistance, but applicable to alternating currents and voltages.

inductor A component exhibiting inductance.

insulator A material through which electric current will not easily flow.

integrated circuit An electronic system, or part of a system, produced on a silicon chip using microelectronic techniques.

intermediate frequency In radio and television, the frequency generated as a result of mixing the local oscillator and incoming signal.

JUGFET--JUnction Gate Field-Effect Transistor.

Karnaugh mapping A visual technique used in the planning of digital systems for the minimization of logic circuits.

LC oscillator An oscillator using an inductor and a capacitor in a resonant circuit as a timing element.

LCD Liquid crystal display. See liquid crystal display.

LED Light-emitting diode.

light-emitting diode (LED) An electronic component in which electric current is converted directly into visible or infra-red light.

line timebase In a television, the oscillator circuits concerned with horizontal scanning of the picture.

linear electronics Electronic systems in which quantities are represented by continuously varying electrical signals. See also digital electronics, analogue.

liquid crystal display (LCD) A reflective display, used in digital systems for the presentation of output. The liquid crystal display is characterized by a very low power consumption.

logic Usually used as an abbreviation for 'digital logic', referring to systems involving logic gates.

luminance In television, the part of the signal concerned with the brightness of the image on the tube.

microcomputer A computer in which the CPU is a microprocessor.

microprocessor A computer CPU constructed using large-scale integration in which all the CPU circuits are fitted into a single integrated circuit.

modulation Variation of the frequency, phase or magnitude of a high frequency waveform in accordance with a waveform of lower frequency.

monostable A system with a single stable state.

MOS Metal Oxide Semiconductor.

MOSFET Metal Oxide Semiconductor Field-Effect Transistor.

multimeter A general-purpose measuring instrument, usually able to measure resistance, current and voltage.

negative feedback--Feedback applied to a system in such a way that it tends to reduce the input signal that results in the feedback.

NiCd Chemical symbols for nickel and cadmium; used to refer to nickel cadmium accumulators.

NMOS n-channel MOS.

npn Negative-positive-negative (although always pronounced 'en-pea-en'); refers to one of the two alternative types of bipolar transistor.

NTSC National Television Standards Committee. The American body that defined the American television standard. 'NTSC' is used to refer to the type of TV system used in the USA.

operational amplifier A highly stable, high gain, d.c. amplifier, usually produced as a single integrated circuit.

optoelectronics Electronic systems or devices that involve the use of light.

opto-isolator An optoelectronic component used to couple signals from one system to another, while retaining a very large degree of electrical isolation between the two systems.

oscillator An electronic system that produces a regular periodic output.

oscilloscope An instrument for displaying electrical waveforms on a cathode ray tube.

Q Ohm: the unit of resistance.

PAL Phase Alternation by Line. The color television system used in the UK and elsewhere. It has advantages over the NTSC system that preceded it.

passive component--A component that does not involve the control of electrons in a thermionic or semiconductor device.

PCB Printed circuit board.

photoresistor Also known as an LDR (light-dependent resistor). A resistor whose value depends upon the amount of light falling on it.

piezoelectric effect--The direct conversion of electrical to mechanical energy, or vice versa, in some crystalline materials.

PMOS p-channel MOS. pnp positive-negative-positive (although always pronounced 'pea-en-pea'); refers to one of the two alternative types of bipolar transistor.

positive feedback--Feedback applied to a system in such a way that the feedback tends to increase the input signal causing the feedback.

potentiometer A variable resistor having connections to each end of the track and also to the brush.

PPM Pulse-position modulation.

program A set of instructions used by a computer.

PWM Pulse-width modulation.

quartz crystal oscillator A very stable oscillator, depending for its stability on the electromechanical properties of a quartz crystal.

RAM Random Access Memory. The main storage area in a computer system.

raster The pattern of horizontal lines produced on a television screen.

relay--An electromechanical device in which an electric current closes a switch.

resistance The property of a material that resists the flow of electrical current.

resistor--A component exhibiting a known amount of resistance.

RF Radio frequency.

ROM Read Only Memory. Used in computer systems to store programs and information that is not lost when the system is switched off.

Rx Abbreviation for 'receiver'.

semiconductor A material with properties that lie between those of insulators and conductors. Extensively used in modern electronics.

Si Chemical symbol for silicon, a semiconductor.

speaker (loudspeaker) An electromechanical device for converting electrical energy into sound.

static RAM Random Access Memory in which information is stored in bistable devices. See dynamic RAM.

superheterodyne A radio receiver system in which the radio frequency input is mixed with a frequency generated within the receiver to produce an intermediate frequency.

teletext Any system that involves production of digitally generated text and pictures using standard television systems.

thermionic Electronic devices involving electrons generated by heat, usually in a vacuum.

thyristor A component similar to a semiconductor diode but having in addition a gate connection by which the component, normally non conducting, can be triggered into conduction.

tolerance Generally the amount by which a specified component value can vary from the marked value.

triac A semiconductor component similar to the thyristor but which will conduct in either direction.

TTL Transistor-transistor logic: one of the two major 'families' of digital logic circuits. Uses more power than CMOS, but is capable of higher operating speeds.

Tx Abbreviation for 'transmitter'.

ultrasonic A frequency above the range of human hearing. Note that 'supersonic' is now generally used to mean 'faster than the speed of sound'.

unijunction transistor A semiconductor device used in some oscillators.

V Volt: the unit of electrical potential.

varicap diode A semiconductor diode in which the junction capacitance varies according to the applied voltage. This effect is inherent in all semiconductor diodes, but in the varicap diode the property is deliberately enhanced. Used in tuning circuits in radio and television.

VDU Visual display unit.

video (a) In television, the demodulated vision signal.

(b) More generally, anything relating to the recording, replaying, transmission or reception of pictures.

wavelength The physical distance between two similar and successive points on an alternating wave.

Zener diode A semiconductor diode, used for voltage regulation. When The Zener diode is reverse-biased, it exhibits a sudden increase in conductivity at a certain specific voltage.

Recommended -- FURTHER READING

The following books may all be of interest; books marked with an asterisk* are suitable for more advanced studies:

L. Basford, Electricity Made Simple (W. H. Allen, 1968).

Graham Bishop, Linear Electronic Circuit and Systems, 2nd ed. (Macmillan, 1983).

J. Cullen, Electrical Drawing I (Macmillan, 1979).

P. E. Gosling, Beginning BASIC (Macmillan, 1977).

*P. E. Gosling, Continuing BASIC (Macmillan, 1980).

P. E. Gosling, Mastering Computer Programming (Macmillan, 1982).

G. King, Beginner's Guide to Radio (Newnes-Butterworth, 1973).

R. Lewis, Electronics Servicing: Theory (Macmillan, 1981).

R. Lewis, Electronics Servicing: Core Studies (Macmillan, 1983).

*J. Millman, Microelectronics-Digital and Analog Circuits and Systems (McGraw-Hill, 1979).

N. M. Morris, Digital Electronic Circuits and Systems (Macmillan, 1974).

*N. M. Morris, Semiconductor Devices (Macmillan, 1976).

G. Wright, Mastering Computers (Macmillan, 1982).

* J. Zarach and N. M. Morris, Television--Principles and Practice (Macmillan, 1979).

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