220V alternating current passes through bulb H and rectifier bridge and becomes DC pulsating voltage, which is applied to VS and R branches of SCR as forward bias. During the day, when the brightness is greater than a certain level, the photodiode D presents a low resistance state of ≤ 1kω, which turns off the transistor V, and its emitter has no current output, and the unidirectional thyristor VS turns off due to no trigger current. At this time, the current flowing through the bulb H is ≤2.2mA, and the bulb H cannot emit light. The resistor R 1 and the zener diode DW make the bias voltage of the transistor v less than 6.8V, thus protecting the transistor. When the brightness at night is less than a certain level, the photodiode D presents high impedance state ≥100K Ω, which makes the transistor V turn on in the forward direction, and the emitter voltage is about 0.8V, which makes the thyristor VS trigger on and the bulb H emit light. RP is a brightness selection element, which is used to switch in the early morning or evening. It consists of an audio amplifier, a frequency selection circuit, a delay start circuit and a thyristor circuit. It provides a sound control lamp with simple operation, flexibility, strong anti-interference ability and sensitive control. It sends out a control signal "hiss" of about 1 s through the human mouth, which can conveniently turn on and off the voice-activated lighting device in time, and has the function of automatic time-delay closing to prevent false triggering, and is equipped with a manual switch, which makes its application more convenient.
Voice-activated lamp is a kind of voice-activated electronic lighting device, which consists of audio amplifier, frequency selection circuit, delay start circuit and SCR circuit. It provides a sound control lamp with simple operation, flexibility, strong anti-interference ability and sensitive control. It sends out a control signal "hiss" of about 1 s through the human mouth, which can conveniently turn on and off the voice-activated lighting device in time, and has the function of automatic time-delay closing to prevent false triggering, and is equipped with a manual switch, which makes its application more convenient. The voice control lamp consists of a microphone, an audio amplifier, a frequency selection circuit, a voltage doubler rectifier circuit, an amplitude discrimination circuit, a constant voltage source circuit, a delay start circuit, a controllable delay switch circuit and a silicon controlled rectifier circuit.