555 photosensitive voice control switch circuit diagram

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

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Photocoupler

The photosensitive voice-activated switch is composed of a step-down rectifier voltage regulator circuit, a voice-activated amplification and shaping circuit, a light control switch, a monostable trigger and a relay control circuit.
In the figure, B is a miniature electret condenser microphone, which can convert an external sound signal into an electrical signal. After the sound signal is amplified by the VT1 voltage amplification stage, it is added to the high-magnification op amp amplification (closed-loop gain 100 times) and compared, the output of the required down-jump signal (the LM741 comparator is normally high), which provides negative power for IC2. Flat trigger signal.