Light-Controlled Sounds

Project Number: 61

OBJECTIVE: To give a more dramatic demonstration of using the photosensitive resistance.

Description: Build the circuit shown on the left. Turn on the slide switch (S1), a police siren is heard. The loudness of the sound depends on how much light reaches the photoresistor (RP), try partially shielding it or placing it near a very bright light, and compare the sound.