This is a low cost emergency light that is based on white LED. The white LED provides very bright light that will turn on in the absence of the main light. This circuit has an automatic charger that stops charging once the battery is fully charged.
It is fitted with IC LM 317 that produces a controlled 7 voltage for the battery charging. The output is driven by transistor BD 140 while the charging of the battery is controlled by Zener diode and Transistor BC 548.