Here is the circuit diagram of a very versatile emergency lamp that can be operated in two modes (flasher and dimmer). The circuit is based on the dual op-amp IC LM358.The dimmer and flasher mode can be selected by using the switch S1. In the dimmer mode the output of IC1b will be pulses whose width can be adjusted by using POT R3. Transistors T1 and T2 forms the driver stage which drives the lamp L1 according to the output of IC1b. In the flasher mode, output of IC1b will be a variable frequency pulse which can be adjusted by POT R3 to obtain 1 to 25 flashes from the lamp.
- The circuit can be assembled on a Vero board.
- Use a 12V battery for powering the circuit.
- A heatsink must be fitted on transistor T2.
- S2 can be used as an ON/OFF switch.
- F1 should be a 2A fuse.
- L1 can be a 12V; 2A incandescent lamp.
- IC1 must be mounted on a holder.