The input circuit of the switching power supply mostly uses a capacitor filter type rectifying circuit. When the incoming line power is turned on, the initial voltage on the capacitor is zero, and the capacitor charging moment will form a large surge current, especially the high-power switching power supply. Larger filter capacitors allow surge currents of up to 100A. Such a large surge current at the moment of power-on, often causes the input fuse to blow or the contact of the closing switch to burn out, and the rectifier bridge is damaged by overcurrent; the lighter will also make the air switch not close. All of the above phenomena will cause the switching power supply to fail to work normally. For this reason, almost all switching power supplies are provided with a soft start circuit for preventing inrush current to ensure normal and reliable operation of the power supply. Figure 3 replaces the RC delay circuit A humidifier is beneficial to increase the air humidity and stabilize the indoor air in a healthy and reasonable state. At the same time relieve dry skin, promote blood circulation and metabolism of facial cells, relieve nervous tension and eliminate fatigue. It is beneficial to protect the respiratory tract and avoid inducing various respiratory diseases. When the air humidity is suitable, it is difficult for germs to spread, which is beneficial to human health. Car Humidifier,Car Air Diffuser Humidifier,Car Mini Humidifier,Car Small Air Humidifier Dongguan Yuhua Electronic Plastic Technology Co.,Ltd , https://www.yuhuaportablefan.com
Figure 1 shows an anti-surge current circuit using a thyristor V and a current limiting resistor R1. At the moment when the power is turned on, the input voltage charges the capacitor C through the rectifier bridges (D1 to D4) and the current limiting resistor R1 to limit the inrush current. When capacitor C is charged to approximately 80% of the rated voltage, the inverter operates normally. The trigger signal of the thyristor is generated by the auxiliary winding of the main transformer, the thyristor is turned on and the current limiting resistor R1 is short-circuited, and the switching power supply is in a normal running state.