No software is required for this chapter. Everything here is physical: a breadboard, a handful of components, and a 5V supply.
Components
From the 74-series logic family:
- 1× 74HC00 DIP-14 — the quad NAND gate. This is the same chip that appears in the f03b/00 parts list for address decode. If you have already ordered parts for f03b, you have one. If not, buy it now — it is a commodity chip, widely available from online electronics retailers, and inexpensive.
Discrete components:
- 1× 2N3904 NPN transistor — a small signal transistor used in the transistor page. Equivalents work too: BC547, BC548, PN2222. Any small NPN in a TO-92 package.
- 6× LEDs — any colour, any standard LED with a forward voltage around 2V. You will use four for binary counting, one for the transistor circuit, and one for gate output verification.
- Several 1kΩ resistors — at least six. These are the current limiters in series with each LED.
- 1× 10kΩ resistor — the base resistor for the transistor circuit.
The platform:
- 1× breadboard — half-size (400-tie) or larger. Solderless.
- 1× 5V power supply — a phone charger with a USB breakout board and screw terminals is sufficient. A bench supply with a current limit set to 200mA is safer: if you wire something wrong, the supply folds rather than heating a component.
- Jumper wires — mixed lengths, male-to-male.
Tools:
- Multimeter — required. Every power check in these pages uses one.
Power
Before seating any chip, wire the power rails on the breadboard and confirm the voltages are correct.
Connect the positive terminal of your supply to the + rail of the
breadboard. Connect the negative terminal (ground) to the - rail. The two
long horizontal strips running the length of the board are the power rails;
all component power and ground pins connect to these.
Confirm with a multimeter:
- Red probe on the
+rail, black probe on the-rail. - Reading should be 5V ± 0.25V.
If the reading is outside that range, check the supply output voltage before continuing. A 5V-only supply from a phone charger is usually well-regulated; a bench supply with an adjustable knob may need trimming.
With the rails confirmed, the breadboard is ready for components.