Why does the emergency light appear when the power supply is normal?
Emergency lights are normally not light during normal power supply, but if the internal wiring has connected the charging and the light switch in parallel, the emergency lights will appear when the power supply is normal.
Emergency lamp control circuit is composed of Q3, Q5, Q7 and K G, in the key, no electricity, press the K key (open), Q5 saturation conduction, the collector current of Q5 by R12 to keep Q7 conduction
When the mains power supply, the external power supply by D9 make the D7 reverse cut-off, Q5 can not be connected, keys K and G can not control the light Ll, L2 on and off.
D11 reverse breakdown in voltage state, the collector voltage of Q5 to Q3, Q4 provide the bias conduction, light L1, L2.
