Fire-Fighting Emergency Light Circuit

Published:2011/8/5 21:15:00 Author:Robert | Keyword: Fire-Fighting, Emergency, Light | From:SeekIC

1. The battery charging circuit external power would charge for the battery with constant current through the Q2, Q6, R8, D10. When there is the external power supply, the charging current would charge the battery trough R8, D10 and also the charging indication lamp D12 would light.The picture shows the fire-fighting emergency light circuit.2.The light control circuit is made up of Q3, Q5, Q7 and key K, G. When there is no commercial power, by pressing the key K (openning), the Q5 would be saturated and conducted. The Q5's collector polar current would maintain the Q7 to keep conducted through R12. The D11 reverse breakdown is working in stable mode. The Q5's collector polar voltage would provide the bias voltage for the Q3, Q4 to make they conducted to light the L1 and L2. When pressing the key G (closing), the Q7 would be closed which remove the conducted conditions of Q5, and the lamp would be off.



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