Maker Electronics Math

What this book teaches

One sum, pointed at thirteen different parts of a real project: what a thing draws, multiplied by how long it is connected. Ohm's law and why you round a resistor up; what a battery actually holds as against what the packet claims; the division that turns a wake interval into a year; the two resistors that can halve a runtime if nobody switches them off; what one ADC step is worth, and why a fine reading is not a true one; calibrating a sensor against ice and stating an error bar you can defend; τ = R × C, and what waiting costs in milliamp-seconds; the pull-up that is free until a lid presses on it; why a quarter of the current looks like more than half the light; the eight-pence part whose datasheet line turns 375 days into 16; storage as a second battery that runs out first; a runtime that is a range rather than a number; and finally the capstone — measure a 30-microamp current on a meter that cannot read it, compare with your prediction, and design the one further test that says which line was wrong. Every chapter carries a boxed, skippable Does It Pay? section, and nothing in the book touches mains electricity.