Circuit Description

The circuit diagram of musical light chaser has been described here. The main parts of this circuit are two transistors Q1, Q2 (BC 107) and IC1, IC2 (CD 4017). Transistor Q1 in this circuit acts as amplifier of the sound signals picked up by the condenser mic. This amplified output from Q1 is given to the clock input of IC1. This IC in this circuit is made to work as divide by ten modes. The output of IC1 is given to IC2 as its clock input. The output of IC2 works with respect to the input signal frequency. The final output is 10 lights dancing with respect to the input sound signal.

If there is no sound signal, then only the first light will glow steadily. The power supply for this circuit is directly taken from mains using a combination of some components. These components consists of diodes D2 and D3 (IN 4007), capacitors C4 and C3 and resistor R9 (10K). This made the circuit compact since this type of powering avoids the use of bulky transformer.

Circuit Diagram

Musical Light Chaser Circuit

Musical Light Chaser Circuit


  • If this circuit output does not respond to the music and only the first light remains glowing, adjust R1 to set the input level of IC1.
  • Due to limited space only one arrangement for connecting only one lamp is shown in the diagram. Make 9 lamp arrangements like the one shown in figure and connect each if them to the each outputs of IC2 with the other ends connected to the circuit as that of one shown in circuit.
  • Extra care should be taken while playing with this circuit since some parts of this circuit are live with shock hazard.