Experiment 16 - The Gated Astable Multivibrator with 555

With a small change to the circuit you can switch the astable multivibrator on and off. To do this you use the RESET input of the 555.

In the circuit shown, you find out how the RESET input is connected.

Circuit diagram gated astable multivibrator with 555.

When you press the pushbutton switch S1, the LEDs LED1 and LED2 are flashing. When you let go of S1, the multivibrator stops and only LED1 is on. This is shown schematically in the illustration.

Circuit gated astable multivibrator with 555. (Enlarge)

Signals of a gated astable multivibrator.

This circuit is known as a "gated astable multivibrator" and is an important circuit in electronics.

But now you manipulate the switching times...