Author: Noyafa–CCTV Tester
The DC resistance tester has entered the era of high-efficiency power conversion equipment, especially the continuous miniaturization of computers, which requires the size of the power supply to be miniaturized. The DC resistance tester has entered the era of high-efficiency power conversion equipment, especially the continuous miniaturization of computers, which requires the size of the power supply to be miniaturized. voltage power supply, while the power efficiency has been significantly improved. The reduction of the volume of the power supply means the deterioration of the heat dissipation capacity, so the power consumption of the power supply is required to be reduced, that is, under the premise of the same output power, the efficiency must be improved. The power dissipation of the same volume of power supply is basically the same. Therefore, in order to obtain greater output power, the efficiency must be improved. At the same time, high power supply efficiency can effectively reduce the stress of power semiconductor devices and improve their reliability.
Switching loss has always puzzled switching power supply designers. Since power semiconductor devices have current and voltage on the device during the switching process, switching loss is inevitable. If the switching tube and output rectifier diode in the switching power supply can achieve zero-voltage switching Or zero-current switching, its efficiency can be significantly improved. The DC resistance tester adopts new technologies, new materials and new devices in the 1990s. It has the characteristics of large output power, small size, light weight, reliable overvoltage, overcurrent and zero closing protection functions, with 0.75 times Voltage latch function, and equipped with time relay, can set timed sound alarm during the test. The switching loss caused by the switching process will roughly account for 5% to 10% of the total input power. Significantly reducing or eliminating this loss can increase the efficiency of the switching power supply by 5% to 10%.
Effective methods are soft switching techniques or zero voltage switching or zero current switching techniques. The DC resistance tester powers up the test product through a high-current constant current source, collects the values of voltage and current, and calculates the resistance value of the test product. The value measured at this time must be the real resistance value of the test product, which prevents the generation of false data.
Even if there is a strong electric field interference on site, due to the small resistance in the voltage DC, the voltage induced to the voltage test terminal is a common mode voltage. Test accuracy has an impact. The above shows that the automatic judgment and prompt function greatly improves the test accuracy and production efficiency, and is a reliable support for the field test personnel to quickly solve the problem.
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