Electronics -- A First Course
by Owen Bishop, Published by Newnes (Second Edition)
ISBN 0-7506-6960-8, paperback, 223 pp, $34.95
EN-Genius Reviewer: Paul McGoldrick
This book was written as an introductory textbook for the UK GCSE Electronics examination (taken at age 16, the equivalent of the old "O" levels). As a book that might be taken up by a child that was just entering secondary education -- the equivalent of Middle School in North America -- I thought that the best initial judge of the book would be such a child, namely my daughter, aged 12.
Over a period of some days she had no problem with Part 1's Electrons; Static and Current Electricity (Current Electricity? What absurd terminology); Cells and Batteries; Current Voltage and Power; and Alternating Current. When it came to Mains Electricity and Plugs and Fuses she was international enough to understand that what was being talked about was UK-centric and was able to move on. She got past Electricity in the Home; Sources of Energy; and More Sources of Energy, but when it came to the first section of Part 2 of the book on Resistance she came to an abrupt halt.
The reason was simple. The tone of the book suddenly changes with Part 2 and you find you are in a hands-on environment, instead of an explanatory one, needing a piece of carbon and a multimeter to continue what could have been just a simple explanation of Ohm's Law with the practical aspect as an optional path. There was no enthusiasm from my daughter to go beyond that point so the grownup had to take her place.
Ohm's Law is not that difficult a concept but one of the "Self Test" questions (that are scattered around the book, and for which the answers bear no relationship to the pages they are actually printed on) is "A 2.3 kW heater runs on the 230 V mains. What is its resistance?" It is not meant as a trick question, but getting an ac voltage in the same sentence as "resistance" rather beggars belief. In the same section the author offers some other considerable confusion with:
"You have already used symbols for units, such as A, V and W. It is useful to have symbols for quantities too. This makes it quicker to write out equations. The symbols for quantity are:
I for numbers of amps
V for numbers of volts
R for numbers of ohms
"Symbols for quantities are in slating letters (italics). Using these symbols instead of words, the Ohm's Law equations become:
R = V/I
I = V/R
V = IR
"Try not to confuse V, which means 'volts,' with V, which means 'numbers of volts.'"
I really didn't know that this Italic claptrap was still being taught by anybody, anywhere.
Resistance and networks are well covered, from a practical point of view, but then the questions in that section launch into current nodes with no explanations whatever. Throughout the student is urged to use the shorthand form for resistance such as 2k2 instead of 2.2 kΩ. It is, again, a practical approach, but the fundamentals need to be instilled first.
Capacitance is reasonably well explained from a charge approach, but in the description of the most popular types of capacitor the ceramic is nowhere to be found. Inductance is explained from a physics point of view, but the explanation of an electric motor and generator are oversimplified to the point of confusion and, for some odd reason, the section ends by getting into further discussion on power and voltage, mains power distribution and high voltage distribution.
SI units and the derived units are quite well covered with a useful charting of multiples and fractional symbols.
The section on switches includes some rather old fashioned parts and makes absolutely no mention of 'make-before-break' or 'break-before-make' parlance and neither solid-state switches or relays are dealt with in any form.
The same bitty coverage continues into diodes, rectifier diodes and LEDs but the latter also covers power diodes and Zeners! Light dependant resistors are next followed by thermistors -- with absolutely no explanation of what the physical nature of a thermistor is.
The text then gets into transistors -- but again there is no explanation of what turns a transistor on or any of the physical facts, but a follow-up section does get into touching on the misleading world of hfe with, again, no explanation of what h parameters are all about. In transistor power switch coverage the example device is a photo of a MOSPEC TO-220 version of the venerable 2N3055 npn audio amplifier (with a 1978 date code). But, then there is no explanation of any difference between npn and pnp or even that such a difference exists. Simplifying the heck out of things sure makes them more understandable, eh?
A rather quaint section on using stripboard (actually Veroboard, to give the manufacturer its due) is followed by decent coverage of thyristors but, again, no physical information about how the gate actually turns the device on.
That is followed by coverage of FETs where the author admits to the existence of n-channel MOSFETs, again without definition, and compares BJTs and FETs with statements like: "BJTs convert current to current. FETs convert voltage to current." Very interesting… The book then does another one of its wobblies by going off on a tangent about protective [sic.] diodes, data sheets and selecting transistors and FETs.
Part 3 of the book (Electronic Systems) opens with a nice description of the parts that are needed for a system flow using real world examples of a scale, a supermarket check out and an ATM but it then wobbles off for a six page diversion on PCBs whereas the logical direction would be to get straight into the sensor part of the system. In that coverage there are reasonable descriptions of temperature, light, force, sound, Hall effect, moisture and position sensors without, of course, any physical information. He also tries to convince us that switches can be sensors, too!
Then there is another wobbly about testing projects before he gets back to how the sensors can be interfaced. He covers Darlington pairs, Schmitt (sic) triggers and comparators -- and all this without mentioning op amps. They come up in the next section dealing with amplification after a three column-inch coverage of audio amplifiers: "The most popular audio amplifiers are the LM380, LM386 and TBA820." National and STMicroelectronics (dating from when the company was still SGS-Thomson) are no doubt grateful for the kudos. Op amp coverage starts off hopeful, but then everything goes wobbly again with talk about noise, EMI, and a transistor pre-amp.
Next we head for a section called Timing which is about monostables (including the venerable, most sold IC in history, the 555 timer), astable circuits and duty cycle definition, all done quite well.
There follows a very nice section on explaining logic, including Boolean notation followed by practical coverage of logic systems except for one disappointing example of driving a seven-segment display -- really up-to-date!
Then there is a section on data memory with the prime example being a 2 kbyte (book uses Kb, yuck!) 6116 but it does at least cover Flash memory. After a new section starts out hopefully on microcontrollers with a picture of a 1997 date-coded PIC, it then wanders off to talking more about memory. A small section on programming follows with a nice positioning between explanation and not getting bogged down with code.
The book follows on with short sections on visual, audible and mechanical output devices; then it moves on to audio subsystems and recording before looking at radio transmission (both AM and FM) and then radio reception (without mentioning the word superhet) and going on to data communication systems. It then looks at the elements of computation and some simple control systems -- including using PIC as a generic processor word instead of acknowledging Microchip. It has a nice last wobble by looking at the operation of a linear voltage regulator -- well, actually, just 78xx regulators.
The book is completed with a supplement on circuit symbols and then the answers to all the questions posed to the reader in the book -- but good luck trying to tie up the listed page references to the real thing.
If this book has been written to a syllabus then the syllabus is bad; if the book has tried to write to a syllabus then the book is bad. It is incomplete in most areas, misleading in others and out-of-date in many places. Missing words, like impedance, make me extremely uncomfortable. I could not recommend the text to any reader, on either side of the Atlantic.
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