Why should we use a wirewound resistor for mobile phone chargers?
Oct 18, 2019| Stay Charging Safely with SChitec
Why should we use a wirewound resistor for mobile phone chargers?
The wirewound resistance is accurate. In theory, unless it is the charger output voltage reference, the general charger does not use wirewound resistors. The mobile phone charger circuit is the SMPS switching power supply circuit. The requirements of the high voltage terminal signal generating circuit are very high. High, it is impossible to use wirewound resistors, otherwise it will lead to self-excitation, which will affect the oscillation frequency, so that the output fluctuates greatly. Only the sampling reference circuit at the low voltage end may use wirewound resistors... A mobile phone charger circuit is not high. Precision electrical equipment does not need to calculate the capacitive reactance and inductive reactance of the PCB board. Moreover, the switching power supply itself fluctuates greatly, and the filtering effect of a wire wound resistor is negligible.
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Wirewound resistors are mainly used to reduce voltage, shunt, load, feedback, energy transfer, matching, etc. in low frequency AC circuits, or act as absorbers and voltage dividers in power circuits, and can also be used as oscillations. Attenuation adjustment in the loop and transformer and shunt in the pulse forming circuit. In addition, it can also be used for discharge and spark suppression of filter stage capacitors in rectifiers. At the same time, it can be widely used in home appliances, medical equipment, automotive industry, railway, aviation, military equipment and other fields.