How much power will the charger consume?

　　In fact, no-load power consumption of a single charger is not large. The People's Republic of China Communication Industry Standard yd-t1591-2009 "Technical Requirements and Test Methods for Mobile Communication Terminal Power Adapters and Charging/Data Interfaces" states that the rated output current of the power adapter should be within the range of 500 mA to 1500 mA , as determined by the manufacturer. The power consumption is less than 150 mW under the no-load energy consumption of the power adapter. The regular chargers we use will meet the relevant national standards. But as mentioned above, if most users' chargers are left on the power supply, the accumulated power consumption is still very shocking.

　　How does the switching power supply use the dummy load to repair the circuit?

　　The switching power supply controls the on and off time of the switch tube in the circuit, and it can continuously stabilize the output voltage in the circuit. It is a relatively mature technology developed in recent years. Dummy load refers to the component that can receive electrical power in a circuit or the output port of the circuit, which is called dummy load. Dummy load also has the ability to detect circuit errors in switching power supplies, so how to use dummy load to check? Senshu Qiang Electronics will focus on this issue.

　　When the load of the switching power supply is short-circuited, the output voltage will decrease, and the output voltage will also increase when the load is open or no-load. In the maintenance, the dummy load replacement method is generally used to distinguish whether the power supply part is faulty or the load circuit is faulty. Regarding the selection of dummy loads, 40W or 60W bulbs are generally selected as dummy loads. The advantage is that it is intuitive and convenient. According to whether the bulb emits light and the brightness of the light, it can be known whether the power supply has voltage output and the level of the output voltage.

　　Compared with the advantages, the disadvantages are also very obvious, mainly reflected in the problem of resistance. For example, the thermal resistance of a 60W light bulb is 500Q, while the cold resistance is only about 50Ω. Assuming that the main voltage output of the power supply is 100V, when a 60W light bulb is used as a dummy load, the current of the power supply is 200mA during operation, but the main load current at startup reaches 2A, which is 10 times the normal operating current. Therefore, the light bulb is used as a dummy load. , It is easy to make the power supply difficult to start, because the higher the power of the bulb, the smaller the cold resistance, therefore, the higher the starting current of the high-power bulb, the more difficult the power supply to start.

　　When calculating the starting current and working current of the power supply, the formula I=U/R can be used to calculate: the load current when the power supply starts is 100V/50Ω=2A, and the load current when the power supply is working is 100V/500Ω=0.2A. However, it should be noted that the above is a theoretical calculation, and there may be discrepancies in practice. In order to reduce the start-up current, a 50W electric soldering iron can be used as a dummy load (900Ω in both cold and hot states) or a 50W/300Ω resistor, which is more accurate than using a 60W bulb.

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