what is the uses of music-operated lights?what is the working of music-operated lights?

Expert Answers
valentin68 eNotes educator| Certified Educator

Music operated lights are usually a set of three to four lights that were used about 20-40 years ago in discotheques and in houses by music lovers to accompany the sounds and produce an intimate atmosphere. The colours of the music lights are chosen from the set of primitive Red-Green-Blue colors used in color TV  such as to obtain from their addition all the possible colors. They were invented for the first time about 150 years ago in Giza, Egypt, where tourists were accompanied by music and lights when visiting pyramids in the evening. 

Basically, the intensity of all the lights is varying according to different portions of the audio spectrum. The red color correspond to low frequencies of the spectrum, the green color corresponds to medium audio frequencies and the blue color corresponds to high frequencies. (The fourth color is the yellow light used for pauses in the audio signal). This is done electronically by using filters for the (audio) electrical signal with different resonant frequencies (usually 100 HZ, 1 KHz and 5KHz, for low, medium and high portions of the spectrum). Initially these were  passive filters made up of simple RLC circuits, but with time to improve the slope of the filters digital filters begin to be used. The filtered signal drives a power AC circuit made up of a controlled rectifier diode, that in turn controls the current through the light-bulbs.

ideabas | Student

it can be used to find out the intensity of sound, like equilaiser display in the music system