to get blinking or flashing effect for example bulbs, LEDs etc.
The circuit is very simple to build and using only few external components. A 100K variable resistor is used to adjust the flip flip rate of the relays per second. The two 1N4007 diodes are used to limit the back EMF of the relay coils. The circuit can be operated from 12 to 15 volt DC.
A very useful, easy and interesting project of a flip flop relay circuit using a 555 IC. The circuit will on and off both the relays one by one continuously and hence any load connected through these relays will go on and off continuously in a flip flop manner. You can connect any DC or AC appliance with the relays