The gas overranging alarm miner lamp 3

Published:2011/7/29 2:59:00 Author:Ecco | Keyword: gas overranging , alarm, miners lamp | From:SeekIC

The gas overranging alarm miner lamp described in the example uses the batteries of miner's lamp as power supply. It is installed in the mine cap.When the gas is over the limit, the alarm signal will remind miners to evacuate in time. The working principle: The gas overranging alarm miner lamp circuit is composed of gas detection circuit,electronic switching circuit and sound alarm circuit. It's shown as the figure 8-31. The gas detection circuit is composed of resistor Rl, and the gas sensor, potentiometer RP. The electronic switching circuit is composed of thyristor VT and RP. Thesound alarm circuit is composed of sound IC, resistor R2, transistor Vand speaker BL. When the gas concentration is below the limit of safety standards, the conductivity between a and b of gas sensor is low, b point is in low level, VT is in the cut-off state, and IC does not work, BL does not sound. When the gas concentration is over the limit of safety standards, the conductivity between a and b of gas sensor will increase, the voltage of b point increases, VT turns on by trigger, and IC works, the audio output signal amplified by the V will drive the alarm BL.



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