This is a mains operated transformerless flasher circuit that can be used for alternately switching a couple of CFL or similar 220V/120V lamp to produce a decorative lighting effect.
Simulation and Working
The below shown design depicts a simple mains operated dual or alternate lamp flasher, which is designed to flash or blink two mains operated lamps alternately at a specific rate as determined by the 100k pot adjustments.
The circuit stage built around T1 and T2 is an ordinary astable multivibrator wherein the transistors switch alternately at a given rate as set by the values of C1, C2 and /or the values of the pots VR1 and VR2.
VR1 and VR2 can be discretely adjusted to produce different sets of flashing rates for the two lamps, or can be fixed in the middle for generating a uniform flashing pattern for the lamps.
The lamps are switched through the indicated triacs whose switching is controlled by the switching rate of the transistors, during the transistor OFF periods the traics are switched ON and vice versa, this effect is not simultaneous, rather implemented alternately for the traics giving rise to the proposed alternate flashing effect for the lamps.
Power Supply
The entire circuit is powered through a simple 12V stabilized transformerless power supply made by using a high voltage capacitor 474/400V, a rectifier diode and a 12V zener diode.
The 100uF capacitor filters the 12V stabilized half rectified output from the 1N4007 output and feeds a clean DC to the rest of the circuit for the intended operations.
THE CIRCUIT IS NOT ISOLATED FROM MAINS, AND IS THEREFORE EXTREMELY DANGEROUS TO TOUCH IN POWERED CONDITION AND WITHOUT AN INSULATED ENCLOSURE
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JAYANATH says
sir i want to flash 3 nos ac bulbs just flash as 1,2,3 1,2,3 so on. request instructions please
Swag says
Hi Jayanth, you can use the following concept
https://www.homemade-circuits.com/make-this-diwali-christmas-running/
use only pin3, 2, 4, for lamp connection and ignore all the rest, and remove pin#15 connection from the ground and connect it with the pin#7
also make sure to use a 50 ohm 1 watt resistor in series with the input capacitor 474/400V
Pradeep Kumara says
sir please indicate the circuit for simple on off flasher for one ac bulb
Swagatam says
Pradeep, you can use the same circuit that's shown above, just eliminate one of the side's triac