The objective of the kit Flasher for Deepawali is to design a circuit for a portable electric lamp-cum-LED flasher. It uses a 25W, 230V AC bulb and nine LEDs. When the bulb glows all the LEDs remain ‘off, ‘and when the LEDs glow the bulb remains ‘off.’. In this kit Flasher for Deepawali .
The kit Flasher for Deepawali is built around timer IC 555 which is wired as an Astable multivibrator generating square wave. The output of 555 Timer drives transistor BC547. When output pin 3 of 555 Timer goes high, transistor BC547 conducts to fire triac BT136 and the bulb glows. Bulb turns off when output pin 3 of 555 Timer goes low. The collector of transistor BC457 is connected to anodes of all the LEDs. So when BC547 is cut-off the LEDs glow, and when BC547 conducts the LEDs go off. In brief, the bulb and the LEDs flash alternately depending on the frequency of 555 Timer. Flashing rates of the bulb as well as LEDs can be varied by adjusting potentiometer. Using On/Off switch, you can switch off the bulb permanently if you do not want it to flash.