Introduction

This is a kit of the Hardware Basics series. Until now we built circuits from separate gates. Real computers of the 1970s were built differently — from catalogue chips: one package holds four gates, two flip-flops or a whole counter, and every pin has a number and a name from the datasheet. That is how Steve Wozniak built the Apple I.

In this kit you build twelve of the best-known 74-series chips — with the same pin names as the real ones — and put each one straight into a small device:

• 74HC00, 02, 04, 08, 32 — logic in packages: an alarm that stays on until Reset;
• 74HC74 — two D flip-flops: a frequency divider, the lamps blink slower and slower;
• 74HC390 and 74HC86 — a decade counter: a stopwatch 00–99;
• 74HC138 — a decoder: a running light on 16 lamps;
• 74HC595 — a shift register: 8 lamps over three wires, as with an Arduino;
• 74HC244 and 74HC245 — bus buffers: shared wires that devices talk on in turn;
• the finale — an electronic dice built from the kit chips.

What you need

The kit is standalone. The gates NOT, NAND, NOR, AND, OR, XOR come from any kit of the series or from lesson 0. Each chip is built from gates or from the chips of earlier lessons, like nesting dolls: the 74HC390 from four 74HC74, the 74HC245 from two 74HC244.

How much it is

The twelve chips are 1,448 transistors. The simplest, the 74HC04, is 12 transistors; the biggest, the 74HC595, is 588: there are sixteen flip-flops inside. The dice is 268 transistors.

This is a model of real chips

What you will get

Lesson 0 — gates from transistors, optional. Then seven lessons: one or two chips and a device on them in each, and at the end the dice. After the kit your library holds the alphabet that computers, arcade machines and calculators were built from.