Connecting the electric circuit to the lighting installation can be on or off the light by whistle. The circuit is built using the UM3763 chip, a switch controlled by sound. Buzzer piezo-ceramic is used in circuit as a microphone. When it captures a tone frequency between 1.2 kHz and 1.8 kHz, output pin 8, will flip (bulb goes off to on, or turn to off).
To control the light, IC1 control a triac through transistor T1. Power
IC1 power is taken directly from the AC network, acting as a capacitor reactance series resistance with low loss. Diodes D1 and D2 form a rectifier and D3 limits the voltage value of about 3.9 V. Since the voltage is low, instead of D2 can be used an LED.