Gas - smoke alarm circuit with Triac

Published:2011/8/29 1:34:00 Author:Jessie | Keyword: Gas - smoke alarm , Triac | From:SeekIC

When it appears combustible gas, the conductanceof gas sensor TGS308will increase.The voltageon potentiometer RP1 sliding points increases from normal 3V to 20V. This increased voltage is added to the transistor VT1 and makes it turn on by the diode and 4.7Ω resistor, then the Triac 2N6070A is turned on. Full-wave AC voltage drives H to produce 90dB sound and alarm. H is 24V AC Delta16003168 alarm. When the gas disappears from the sensor, the circuit recovers to its original state, so the alarm automatically stops.



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