A multi-vibrator circuit is a circuit that has identical components arranged on the left and right hand sides. The two PNP transistors, the capacitors and the LEDs are the key components. This circuit will trigger itself repeatedly and in this way the LEDs flash alternately. Increasing the value of the two electrolytic capacitors increases the time each LED remains on/off. The transistors are general PNP type. It is important to protect the LEDs and this is achieved by adding the 1k (or lower if necessary) fixed resistors.