Science Experiment 420

Build the circuit as shown, turn the timer lever counterclockwise to set it to the normal on position. The timer and flashlight will always be on.

Make the circuit as shown, turn the timer handle clockwise until you need it (up to 30 minutes), the flashlight turns on, the timer starts the countdown, continues until the end of the set time and the flashlight turns off.

Build the circuit as shown, the process is the same as above.