Circuit Diagram
How to Build It
- Place the NE555 timer on the breadboard.
- Connect pin 8 (VCC) to the positive rail and pin 1 (GND) to the negative rail.
- Connect a potentiometer between pin 7 (DISCHARGE) and pins 6/2 (THRESHOLD/TRIGGER, tied together).
- Connect a capacitor between pin 6 and GND — sets the base frequency.
- Connect pin 3 (OUTPUT) to a BC337 transistor's base through a resistor.
- Connect the transistor's collector to one motor terminal, the other terminal to the positive rail.
- Connect a 1N4007 diode across the motor (voltage-spike protection).
- Turn the potentiometer — the motor speed should vary smoothly.
Bill of Materials
| Product | Code | Qty |
|---|---|---|
| Potentiometer knob block | 57 211 57212 | 1 |
| Integrated circuit | — | 1 |
| Capacitor (electrolytic/ceramic/SMD/film) | 860020674015 | 1 |
| Diode/bridge rectifier | 1N4007-DIO | 1 |
| Resistor | DR47K-8/9 | 1 |
| Transistor (incl. IGBT) | — | 1 |