Two people (or two teams) can used the quiz buzzer to show who pressed their button first. When the button is pressed the buzzer sounds and either the red or green light is illuminated to show who was fastest.

This project is brilliant for demonstrating a wide range of electronics. It uses push to make & push to break switches, thyristors as latches, transistors, logic gates, LEDs & buzzers.

Requires x3 AA batteries, available separately.