Simple and practical production of emergency lights. It can automatically switch power supply in the event of a power outage. When the normal power supply, the backup battery is automatically charged, and there is a charging protection function. The following describes how it works. When the power supply is normal, the J2 is electrically sucked, its moving contacts are connected with the "n/o (often open point)", and the positive end of the backup battery is stimulators are with the reverse phase of the IC1. IC1 (LM308) and D5, D6 are composed of voltage comparators, the reference voltage is determined by D5, D6. A silicon diode (D5) and a 6.2V voltage regulator diode (D6) are used here to form a 6.9V reference voltage to monitor the charging voltage. When IC1 's 2-foot input voltage (both battery voltage) is less than 6.9V, IC1 's 6 foot output high level, T1 Guide, J1 Power, its moving contacts and "n/o (often open point)" connected, the power supply voltage through the R2 to charge the battery, at the same time LED2 lit for the charging indication. Changing the R2 resistance can adjust the charging current.
With the increase of charging time, the 2 foot voltage of IC1 gradually increases, when the voltage is greater than 6.9V of reference voltage, IC1 6 foot output low level, T1 cutoff, J1 power loss, disconnect the charging circuit, to achieve automatic charging protection function. When the power outage, J2 lost the power supply, its moving contacts and "n/c (often closed point)" connected, the battery through the S1 to the emergency lamp circuit power supply, the realization of power outage automatic switching function. S1 is used here to manually cut off the emergency light circuit portion. The emergency lamp circuit is composed of IC2 (NE555), T2, T3, T4 and X2. IC2 composed of 50Hz signal generator, by IC2 's 3 foot output 50Hz signal, by T2 reverse phase, amplification respectively drive by T3, T4, X2 composed of push-pull circuit, in the high-pressure side of X2 induction 220V AC power, so that the fluorescent tube light. The X2 here can directly use a secondary 4.5 kv, primary 220V finished power transformer, the power of the test fluorescent tube depends on the power.
When using, pay attention to T3, T4 should be added radiator. When making, the X1 selects a power transformer with a secondary 6v/200ma. J1 and J2 use relays with a coil voltage of 6V. Other device selection can refer to the diagram, no special requirements. Circuit debugging is very simple, when connected to the main power supply, J2 should move, LED1 for the power supply indication. Then measure whether the 3 foot voltage of the IC1 is about 6.9V, after which an external power supply can be used to connect the IC2 foot to adjust the charging protection circuit. When the input voltage is greater than 6.9V, the J1 should be disconnected. Short open S1, with external power supply access to the emergency lamp circuit, to measure whether the output of IC2 50Hz, and then can be measured X2 output part of the voltage is about 220V can be.
LED3 is a power outage/emergency light work instruction.