555 five-purpose three-state audio logic pen circuit diagram

As shown, the controller includes buck rectifier, monostable and AC solid state relays. 555 and R2, RP1, C4, etc. form a monostable circuit. When AN is pressed , pin 3 of 555 is at high level, which turns on the AC output terminal of the AC solid-state relay, connects the load, and starts timing. The timing time, that is, the temporary stable time of the monostable state td=1.1RP1C4, the maximum timing of the parameters shown in the figure is about 30 minutes, which can be adjusted by adjusting RP1.

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