This is the simplest circuit that mains powered light bulb to flash. To build this circuit we do not need a much money. This circuit can be used in small parties and similar occasions. This circuit is made by wiring a fluorescent lamp starter and a normal light bulb in series. So the light bulb will flash on and off in a flickering sort of way because the starter kicks in and out randomly. This circuit uses a fuse in series with starter and normal light bulb to prevent serious damage on the circuit. For 5-60W light bulbs we can use this circuit, because the fluorescent will handle it without any problems. Here is the circuit :
When the circuit is powered, a bimetal strip inside the fluorescent lamp starter is in open condition, the gas is ionized, a visible arc is produced, and heat is generated. Now the incandescent light bulbs is off since the ionization current is very small, only enough to heat up the ionized gas inside the starter. After a while, the heat makes the bimetal close and shorts the contact, and the ionization inside the starter stops. When this bimetal is shorted, it doesn’t generate heat anymore because now its contact resistance is almost zero compared to the resistance of incandescent bulb, and now the incandescent light bulb is on. After a while the bimetal strip is cooled down, open the contact, and the cycle restarts.
