This is the traditional version of an astable multivibrator that makes two LEDs flash alternately at a frequency that depends on the capacitors used. The circuit is powered by 12 V and the transistors can be BC548 or equivalent for general use.

This is the traditional version of an astable multivibrator that makes two LEDs flash alternately at a frequency that depends on the capacitors used. The circuit is powered by 12 V and the transistors can be BC548 or equivalent for general use.