Circuit Diagram
How to Build It
- Place the NTC thermistor on the breadboard, in series with a fixed resistor, forming a voltage divider.
- Connect the divider's junction to a BC337 transistor's base, through a resistor.
- Connect the transistor's collector to one fan terminal (or fan relay), the other terminal to the positive rail.
- Connect a 1N4007 diode across the fan (protection).
- Connect the emitter to GND.
- Gently warm the thermistor (with your fingers) — the fan should switch on.
Bill of Materials
| Product | Code | Qty |
|---|---|---|
| Diode/bridge rectifier | 1N4007-DIO | 1 |
| NTC thermistor | NTC0603-10K-B1 | 1 |
| Resistor | DR47K-8/9 | 1 |
| Transistor (incl. IGBT) | — | 1 |