In this electronic project, we are going to make a “Temperature Controlled DC Fan using Thermistor“. Temperature Controlled DC Fan is basically a temperature-based fan. It cools the devices by operating a dc fan when the temperature in its surrounding area increases above the preset level. The operation of a Temperature Controlled DC Fan is fully automatic. It turns off automatically when the temperature returns to normal.
Hardware Components
The following components are required to make Temperature Controlled DC Fan Circuit
| S.No | Components | Value | Qty |
|---|---|---|---|
| 1. | Breadboard | – | 1 |
| 2. | Battery | 9v | 1 |
| 3. | Connecting Wires | – | 1 |
| 4. | Op-Amp IC | LM358 | 1 |
| 5. | NPN Transistor | BC548 | 1 |
| 6. | Thermistor | 4.7k | 1 |
| 7. | Resistors | 4.7k | 2 |
| 8. | Potentiometer | 4.7K | 4 |
| 9. | DC Fan | 5V | 1 |
LM358 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of LM358
Temperature-Controlled DC Fan Circuit
Working Explanation
The basic working principle of the Temperature Control DC Fan is based on the working of the thermistor. Here, LM358 compares the voltage across the thermistor and the voltage across the resistor. At room temperature, the voltage across the thermistor will be greater than or equal to the voltage across the resistor.
When the temperature rises above the preset value, thermistor resistance decreases so does the voltage across it. Thus, if this voltage is lesser than the voltage across the resistor, the transistor turns on. It means the motor will start to rotate (The fan starts). Similarly, it will turn off when the voltage across the thermistor rises again (i.e. back to room temperature)
Advantages
- It is economical and easy to handle
- Fan runs automatically
- It is easy to install in heat-dissipating devices to cool them down
- Saves energy by turning off the fan automatically at room temperature
Applications
- It can be used to control the temperature of devices, rooms, electronic components, etc
- It can be used as a cooling pad for laptops or computers
