1. Transistor as a switch board

Components: Built-in with potentiometer
Transistor: Externally mounting type
Output: Via LED

2. Power supply

Regulated DC power supply
Voltage: 5V/1A DC
Rated Input: 220 V/50 Hz or 110 V/60 Hz
Power consumption: <20 W

3. Digital DC voltmeter

Display: 3½ digit, LED
Range: 20 V
Resolution: 0.01 V

4. Patch cords

Set of standard 2 mm patch cords of different lengths with spare cords