Fully automatic appliance protector circuit schematic

LC03-3.3 SOP8 TVS Static Protection 3.3V

As shown in the figure, the automatic appliance protector has the function of large control power, which can stop output when the power supply voltage is higher than 250V or lower than 170V, and automatically supply power when the power supply is restored after 5ms. During normal power supply, the pulsating voltage of D3 rectification is compared with the reference voltage, so that the 3 pin of ICl outputs a rectangular pulse voltage, which makes TWH8778 turn on the output high level to make the triac turn on, and the load is energized. When the grid voltage is greater than 250V or less than 170V, ICl is in protection state and has no output. The output socket of the circuit has no electricity. When the grid is powered off and the power is restored, the C4 has been discharged. When the power supply is restored, the C4 is charged to the high-potential IC2 to trigger the SCR to be turned on. This circuit needs to be delayed by 5 minutes.