Since the pure inverter for car cigarette lighter circuit generally has a power-on soft-start function, it will take 5s-30s after the power is turned on before there will be an output of AC 220V, and the LED indicator will light up at the same time. When the LED indicator is off, it means that the inverter circuit is not working.

The manufacturer of pure inverter for car cigarette lighter tells you that when the power is turned on for more than 30s and the LED indicator has not turned on, you need to measure the AC voltage value at the XAC output socket. If the voltage value is about 220V, it means that only It is the circuit of the LED indicator part that is faulty; if the AC voltage value at the XAC output socket is measured to be 0, it means that the cause of the fault is that the inverter circuit in the front stage of the inverter is not working, which may be the protection circuit inside the chip IC1 has been activated.
The pure inverter for car cigarette lighter manufacturer tells you that the method to judge whether the internal protection circuit of chip IC1 is activated is: use the DC voltage block of a multimeter to measure the DC voltage value of pin 3 of chip IC1 to ground. If the voltage is above 1V, it means that the internal The protection circuit has been activated, otherwise it indicates that the fault is caused by the action of the non-protection circuit.
If the voltage value of pin 3 of chip IC1 to ground is above 1V, indicating that the protection circuit inside the chip has been activated, it is necessary to further use the DC voltage block of the multimeter to test the DC voltage between pins 15 and 16 of chip IC1, as well as the DC voltage of chip IC1. DC voltage between pins 1 and 2. The pure inverter for car cigarette lighter manufacturer tells you that under normal circumstances, the DC voltage of pin 15 to ground of IC1 in the circuit should be higher than the DC voltage of pin 16 to ground, and the DC voltage of pin 2 to ground should be higher than the DC voltage of pin 1 to ground. Voltage, only when these two conditions are met at the same time, the DC voltage of pin 3 of the chip IC1 to the ground can be about 0V, and the inverter circuit can work normally. The manufacturer of pure inverter for car cigarette lighter tells you that if you find that a certain test voltage does not meet the above relationship, you only need to find the cause of the fault according to the corresponding branch, and the problem can be solved.