Emergency light

Posted on Jun 13, 2012

This simple circuit providers battery operated emergency lighting instantaneously upon failure of the regular ac service. When line power is restored, the emergency light turns off and the battery recharges automatically. The circuit is ideal for use in elevator cars, corridors and similar places where loss of light due to power failure would be undesirable. Completely static in operation, the circuit requires no maintenance. With ac power on, capacitor CI charges through rectifier CRI and resistor Rl to develop a negative voltage at the gate of the C106Y SCR

Emergency light
Click here to download the full size of the above Circuit.

By this means, the SCR is prevented from being triggered, and the emergency light stays off. At the same time, the battery is kept fully charged by rectifier CR2 and resistor R2. Should the ac power fail, CI discharges and the SCR is triggered on by battery power through resistor R3. The SCR then energizes the emergency light. Reset is automatic when ac is restored, because the peak ac line voltage biases the SCR and turns it off.

Leave Comment

characters left:

New Circuits



Popular Circuits

Light/dark relay switch
Motor direction controller
Stereo Tv Decoder Circuit
Frequency to voltage converter
Simple LM317 variable voltage supply does it limit current too
bikelab report 2 the sun lab and led taillights
Long-Range IR Transmitter
Model Railway Short-Circuit Beeper
Schematic of the endoelectronics Biotechnology
INA321 OPA340 composed output buffer circuit 322