Timer LM555 Circuits

Posted on Oct 17, 2012

The following are LM555 timer circuits that have unusual functions. Designed to time a sports event; In this circuit the GREEN output is adjusted to be on for 3 minutes and then the RED output is set for 1 minute in a repeating cycle. Each time the light changes a buzzer will sound for about 2 seconds.

Timer LM555 Circuits
Click here to download the full size of the above Circuit.

The timing cycle can be stopped and reset/started with the push buttons shown on the schematic.

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