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Posted by shubham1988 - 10-04-2017, 08:32 PM |
Description. This circuit can give a visual indication of the rate of air flow.It can be also used to check whether there is air flow in a given space. The filament of a incandescent bulb is the sensing part of the circuit.When there is no air flow the resistance of the filament will be low.When there is air flow the resistance drops , because the moving air will remove some of the heat generated in the filament.This variations in the resistance will produce variation of voltage across the filament.These variations will be picked up by the opamp (LM339) and the brightness of the LED at its output will be varied proportionally to the airflow. Circuit diagram with Parts list. air-flow-detector_circuit.JPG Notes. The filament L1 can be made by removing the glass of a 40W incandescent bulb. The circuit can be powered from a 12 V DC power supply. You may also like: Proximity detector circuit Digital thermometer circuit Water level Controller Liquid level indicator Digital compass circuit We recommend: LED lamp circuit from scrap Molecular Self-assembly in Nanotechnology Metal Semi-conductor FET (MESFET) Bit rate Vs Baud rate - the common misconception Simple 100W inverter circuit. |