One of the lighting sound and light control switch circuits

The characteristics of the lighting sound and light control switch are: during the day or when the light is strong, under the action of the light control circuit, the switch is disconnected and
self-locked, the sound control does not work, and the EL light does not light up. At night or when the light is dark, the switch automatically enters the preparatory state
. At this time, when there are footsteps or claps, the switch automatically turns on, the light lights up, and after a delay, it turns off and the light
goes out.
(1) Lighting sound and light control switch circuit one.
    Figure 2-111 is the JKS-I sound and light control switch circuit . The sound control is controlled by the receiver (piezoelectric ceramic chip) HTD; the light control
is controlled by the photoresistor RG. The delay circuit is composed of transistor VT], resistor R3 and capacitor C2 (delay is about 1 min), and
the delay time is determined by R3 and Cz.