How Does Automatic Airflow Sensor Circuit Diagram Work?

This circuit is able to trigger a sign when there is an airflow. The sensor used in this circuit is the bulb filament. If there is no airflow, the resistance of the filament will be low. On the other hand, if there is an airflow going through the filament, the resistance will be varied. It is caused by the filament temperature difference. The resistance variation also affecting the voltage variation of the filament. This voltage variation will be processed by the op-amp LM339 and then displayed by the LED.

Automatic Airflow Detector Schematic Diagram

Here is the circuit :

Automatic airflow detector circuit diagram by documentbuzz

Simple Automatic Airflow Detector Circuit Diagram Components

1. LED1 : LED 5mm
2. Resistor R1 : 100 ohm
3. Resistor R2 : 470 ohm
4. Resistor R3 : 10k ohm
5. IC1 volt regulator : LM 7805
6. Polar Capacitor C1 : 47uF / 15V
7. Potentiometer R4 : 100k ohm
8. Resistor R5 : 1k ohm
9. IC2 Op-Amp : LM339
10. Bulb filament
11. 12V Power Supply

Estimated Price : $1

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