Night warning light circuit composed of multiple resonators

Industrial Router Crystal 3.2*2.5mm 3225 26M (26.000MHZ) 12PF 10PPM 20PPM 30PPM

The above figure shows a nighttime warning light circuit composed of a multivibrator. The circuit is mainly composed of a photoresistor RG, a power supply circuit, a time base integrated circuit IC (NE555), a thyristor VT1 and related components.

After the circuit is powered on, the AC 220V voltage is first stepped down by cl, VD rectified, VS1, VS2 regulated, and output DC voltage of about 12V to supply power to each component in the circuit.

When the light is sufficient, the photoresistor is in a low-resistance state, the 4 pin of the integrated circuit 1C is in a low state, the lc does not work, and the warning light EL does not light.

When the brightness of the night light decreases, the resistance value of the photoresistor becomes larger, the voltage of the 4th pin of the IC rises, lC starts to work, and the oscillator circuit formed by the peripheral components starts to oscillate, so that the 3-pin output oscillating signal drives the thyristor VT1 according to The certain frequency is turned on and off, and the warning light flashes.