Alumni of Harvard's legendary Physics 123 Laboratory Electronics course tend to remember it as a fun, eye-opening, and empowering experience. Half a dozen of my Penn colleagues learned electronics in that course. It was by far my favorite college course. Learning the Art of Electronics embodies that complete course, minus the homework and exam problems. Hence the apt subtitle: A hands-on lab course.

The book is long—twice as long as the 1989 edition (Student Manual for the Art of Electronics, by Hayes and Horowitz)—but self-contained and modestly priced. Unlike its predecessor, the 2016 edition aims to be a complete textbook, so there is no need for students to read Horowitz and Hill (The Art of Electronics). This change is welcome, since Horowitz and Hill is better as a reference than as a student's first introduction. Tom Hayes puts the intuitive Art-of-Electronics spirit into an approachable form that a beginning student can easily digest.

The three times I have taught our physics department's electronics course, I have used many parts of Tom Hayes's updated labs, in draft form. Now that the book is in print, one colleague and I are looking forward to working together through the whole set of analog labs next summer, and we would like eventually to do the digital labs as well. If Learning the Art of Electronics had been published before I first taught electronics, I would have used it verbatim. Even now, I am tempted to do so in future years.

The book's approach is to build intuition and to teach “by immersion,” favoring limiting cases and metaphors over math: large (small) resistance dominates in series (parallel); a low-pass filter's capacitor is like a bathtub; “A transistor is a valve, not a pump;” “When the transistor is saturated, the current is limited not by the transistor but by the load;” for the input resistance of an RC integrator or differentiator, simplify the problem by considering the dc and high-frequency limits. One colleague found the author's intuitive explanation of proportional-integral-derivative (PID) controllers far more illuminating than the mathematical descriptions found elsewhere. The preface notes, “To learn circuit design you do not need to know any substantial amount of physics or sophisticated math.” But students looking for a mathematical approach will need outside references (e.g., Eggleston's Basic Electronics), or perhaps your own supplementary notes. A nice example of Hayes's approach (p. 164) considers impedances along the signal path of an emitter follower, then shows the “clipping” of too large a signal.

Several key “art of electronics” themes are woven throughout the book so memorably that I can say (from my own experience) that one remembers them decades later. The pervasive “10× rule of thumb,” Zin(downstream) > 10 Zout(upstream), “allows us to design circuit fragments independently.” Negative feedback lets an op-amp's output (seemingly magically) calculate the “inverse dog” to undo nearly any “dog” that you throw into your op-amp's feedback loop. Too large a phase shift within the loop creates a sign flip, turning negative feedback into positive, often leading to parasitic oscillation.

I like the illustrations. A beautifully concise cartoon (p. 167) compares emitter follower, current source, common-emitter amplifier, and switch. A longer sequence of cartoons (p. 232) summarizes the steps in analyzing key transistor circuits. Another gem (p. 297) redraws the op-amp “T network” trick (avoiding huge feedback resistors) to make its function obvious. The mechanism and adjustment of a 10 × probe (p. 111) are clearly drawn. Oscilloscope graphs of sampling artifacts (p. 738) explain aliasing. Learning to read logic timing diagrams (p. 834) helps to interpret data sheets or debug Field Programmable Gate Array (FPGA) code. Even the humble 4-pin pushbutton switch (p. 625) is demystified with a figure.

The book is generally good at motivating each topic. The “Thevenin” problem (p. 3): “Given a constant DC voltage source, design a lower voltage source, strong enough to ‘drive’ a particular ‘load’ resistance.” A classroom demonstration (p. 203) illustrates the power of differential signaling, hence differential amplification. And each chapter begins with a “Why” paragraph, such as “In [Chap. 5] we meet an amplifier sensitive to a difference between two inputs… [which] permits implementation of the hugely important operational amplifier,… our principal analog building block.”

A key strength of the book's lab exercises is forcing students to make choices. Designing simple RC filters (p. 84) to separate “signal” from “noise” is a fun exercise, involving more thinking than cookbook steps. The memorable challenge to build a simple AM radio receiver (p. 135) reads, “We have offered you only a strategy, not part values.” To avoid frustration, many questions posed are answered in footnotes. And particularly in the digital labs, the student's task is kept manageable with an otherwise complete schematic containing a dashed box marked “your logic” (p. 729) for the sub-circuit of the student's design, or a block of code (p. 848) with just one missing instruction for the student to fill in.

The book is filled with practical information and advice: it is easy to blow the digital multimeter's fuse when measuring current; poor grounding can evoke LC resonant waveforms (p. 118); amplifier circuits need power-supply decoupling (p. 169); why inductors are used so much less widely than capacitors in low-frequency circuits (p. 112); tips to eliminate or debug parasitic oscillations (p. 370); switching an inductive load leads to voltage spikes (p. 175), cured with a parallel diode—later (p. 445), these spikes are exploited to make a voltage-boosting switching power supply; using pulse-width modulation to drive a motor (p. 340) preserves good torque even at low speed (vs reducing voltage); “floating” the function generator (p. 211) is a neat lesson in chassis grounding; a series resistor (p. 364) can keep an op-amp from oscillating when driving a long cable; 3.3-V vs 5-V logic (p. 692). Real-world language is spelled out in “jargon” sections (e.g., p. 139) and is used throughout the text.

The book is informal and non-mathematical, but does not commit the sin of omission; glossed-over subtleties appear in footnotes (or pointers to Horowitz and Hill) for the ambitious student. “Better filters” (multi-pole, active) are mentioned parenthetically (p. 73) so that one knows the simple RC is not the only filter available. A footnote (p. 290) contrasts “unity-gain frequency” and “gain-bandwidth product.” New supplementary chapters contain “technical” stuff, such as the intuitive model of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) operation, that one can skip on a first reading.

The most welcome change since the 1989 student manual is that each lab's vastly expanded “notes” make this book self-contained. Discrete BJT (Bipolar Junction Transistor) circuits are nicely cut to just two labs, and Junction Field Effect Transistors (JFETs) are eliminated altogether. The “Miller effect” and the “cascode” have moved to footnotes. Current mirrors and the “Early effect” are in a supplementary note. Chapter 9 on parasitic oscillations is new. The new voltage-regulator lab includes designing a linear regulator (which recaps tricky Chap. 9 topics) and a lesson on switching regulators in buck, boost, and inverting configurations. Karnaugh mapping and the JK flip-flop are declared obsolete. A few pages describe delta-sigma ADCs. An appendix on transmission lines nicely illustrates improperly terminated waveforms. The digital labs emphasize programmable logic (FPGAs) and microcontrollers—today's Swiss Army knives of digital interfacing; an appendix introduces Verilog for FPGA programming. The new, fun, PID motor control lab provides great practice using op-amps. The group audio project looks like great fun (I have not tried it) and a nice review of analog topics; it includes a “Debugging strategies” section for testing a complicated circuit block-by-block. The CPU labs now use an 8051 microcontroller instead of a 68008. A new web site, learningtheartofelectronics.com, includes source code and clickable parts lists.

Several labs are particularly memorable. Building a homemade op-amp (p. 217) is really fun, particularly if one permutes the order of topics (a significant departure from the book) to introduce op-amps before teaching transistors. Watching the op-amp's feedback cancel the push-pull follower's “crossover distortion” (pp. 218, 260) is indeed “magical.” Turning a lamp on and off by touching one hand to the gate of a Field Effect Transistor (FET) switch and the other hand to +5 V or ground (p. 487) illustrates an FET's gigantic input resistance. Using the integrator circuit to infer Ibias and Voffset of an op-amp (p. 304) is neat; it always seems surprising that one can “just float the input” to remove the effect of Voffset. Building our own computer, chip by chip, was incredibly fun back in 1991; I look forward to trying the updated microcomputer labs.

The book is divided into 26 class meetings, the first 13 of which cover analog circuits; the last 13 cover digital logic, then microcontrollers. Each class has a “notes” chapter to read beforehand, a set of lab exercises (3–4 h work), some design-oriented “worked examples,” and often a set of supplementary details. Each notes chapter is a quite manageable semiweekly reading assignment, far easier to read than a typical textbook. Many digital labs require a custom LCD display card and a keypad board; both should be available some time in 2016. The microcomputer labs follow two parallel paths: learn to program a commercial 8051 microcontroller module, or build up a “big board” computer chip by chip on a custom circuit board that the author can fabricate on demand. The Harvard course moves at a frenetic pace. One could fill a semester with the 13 analog labs and a few of the digital labs. Even if you choose a simpler microcontroller platform, like Arduino, the 8051-based labs are filled with ideas you could adapt. As evidence of the creativity inspired by the course that this book embodies, the gallery (Chap. 26) of past student projects is simply awesome!

Bill Ashmanskas is a Senior Lecturer in Physics and a staff scientist in Radiology at the University of Pennsylvania. He teaches physics and electronics and works on instrumentation development for positron-emission tomography.