This introduction to circuit design is unusual in several respects。 First， it offers not just explanations， but a full course。 Each of the twenty-five sessions begins with a discussion of a particular sort of circuit followed by the chance to try it out and see how it actually behaves。 Accordingly， students understand the circuit's operation in a way that is deeper and much more satisfying than the manipulation of formulas。 Second， it describes circuits that more traditional engineering introductions would postpone: on the third day， we build a radio receiver; on the fifth day， we build an operational amplifier from an array of transistors。 The digital half of the course centers on applying microcontrollers， but gives exposure to Verilog， a powerful Hardware Description Language。 Third， it proceeds at a rapid pace but requires no prior knowledge of electronics。 Students gain intuitive understanding through immersion in good circuit design。