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Rangkaian Pendeteksi Angin

Tuesday, March 13, 2012 by skemarangkaian

Rangkaian Pendeteksi Angin
This circuit uses an incandescent lamp to detect airflow (mendeteksi angin). With the filament exposed to air, a constant current source is used to slightly heat the filament. As it is heated, the resistance increases. As air flows over the filament it cools down, thus lowering it's resistance. A comparator is used to detect this difference and light an LED. With a few changes, the circuit can be connected to a meter or ADC to provide an estimation on the amount of air flow. 

LM339 Pinout
The glass will have to be removed from L1 without breaking the filament. Wrap the glass in masking tape and it in a vise. Slowly crank down until the glass breaks, then remove the bulb and carefully peel back the tape. If the filament has broken, you will need another lamp.

List Component 
R1   : 100 Ohm 1/4W Resistor 
R2   : 470 Ohm 1/4W Resistor 
R3   : 10k 1/4W Resistor 
R4   : 100K 1/4W Resistor 
R5   : 1K 1/4W Resistor 
C1   : 47uF Electrolytic Capacitor 
U1   : 78L05 Voltage Regulator 
U2   : LM339 Op Amp 
L1   : #47 Incandescent lamp with glass removed (See "Notes") 
D1   : LED

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