Operation of the circuit. When the circuit to the power supply. Is current flowing through R1 and LED1 LED1 light of the C1 will serve to filter noise ground. Voltage drop across LED1 is to be paid to voltage signal generator IC1 out of three legs then the amplifier Q1, Q2 connected together in a darlington transistor. In order to drive speakers with R1, R2 in Limited current circuit will flow through each device to prevent equipment damage.