Strobe the House Lights

Project Number: 56

OBJECTIVE: To use the spinner to see the strobe effect due to 60 cycles.

Description: Use the circuit from Project #55. Setup: Place the spinning rings under a fluorescent light that runs on normal house current. Start the disc spinning and release the press switch (S2). As the speed changes you will notice the white lines first seem to move in one direction then they start moving in another direction. This effect is because the lights are blinking 60 times a second and the changing speed of the motor acts like a strobe light to catch the motion at certain speeds. To prove this, try the same test with a flashlight. The light from a flashlight is constant and if all other lights are out, you will not see the effect that looks like a helicopter blade in a movie. Some fluorescent light use an electronic ballast and they also produce a constant light.