The earliest electronic computers were large, expensive machines built from vacuum tubes, relays, and miles of wiring, yet they established the logical principles that underpin every digital device.The earliest electronic computers were large, expensive machines built from vacuum tubes, relays, and miles of wiring, yet they established the logical principles that underpin every digital device in use today. This book offers a clear introduction to how those pioneering systems actually functioned, from the basic behaviour of electrical switches to the binary arithmetic at the heart of all computation. You will find straightforward explanations of logic gates, memory circuits, and the step-by-step processing of instructions, set in the context of the machines and engineering decisions that shaped the field. Written with the help of artificial intelligence, this text-only guide is intended for curious readers who want a grounded, accessible account of a formative chapter in the history of technology.The earliest electronic computers were large, expensive machines built from vacuum tubes, relays, and miles of wiring, yet they established the logical principles that underpin every digital device in use today. This book offers a clear introduction to how those pioneering systems actually functioned, from the basic behaviour of electrical switches to the binary arithmetic at the heart of all computation. You will find straightforward explanations of logic gates, memory circuits, and the step-by-step processing of instructions, set in the context of the machines and engineering decisions that shaped the field. Written with the help of artificial intelligence, this text-only guide is intended for curious readers who want a grounded, accessible account of a formative chapter in the history of technology.