Gas-sensitive alarm circuit 4
Source: InternetPublisher:张小哥 Keywords: Alarm circuit BSP transistor intermediate relay Updated: 2020/04/29
It uses transistor VTi as a contactless switch, KD9561 analog sound integrated circuit A is amplified
by transistor VTz to drive speaker B to alarm, and intermediate relay KA is used to control the operation of the exhaust fan. When the concentration of the gas to be measured
weakens, the alarm and exhaust will stop.
Adjust the potentiometer RP to change the sensitivity of the device.
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