Main parameters of high-voltage rectifier diodes and methods for detecting high-voltage rectifier diodes

Main parameters of high-voltage rectifier diodes and methods for detecting high-voltage rectifier diodes

Semiconductor diodes are used in almost all electronic circuits and play an important role in many circuits. They are one of the earliest semiconductor devices and have a wide range of applications. How much do you know about high-voltage rectifier diodes? The high-voltage rectifier diode series products are high-voltage rectifier devices composed of multiple micro unit PN junction chips doped with special metals, using a unique process and embedded heat dissipation patented technology combination to achieve a layered unit structure that is resistant to high voltage and high current. What are the main parameters of high-voltage rectifier diodes? How to check the quality of high-voltage rectifier diodes?

Main parameters of high-voltage rectifier diode:

1. Maximum average rectified current IF: refers to the maximum forward average current allowed to pass through the diode during long-term operation. The current is determined by the junction area and heat dissipation conditions of the PN junction. When using, it should be noted that the average current through the diode should not exceed this value, and the heat dissipation conditions should be met. For example, the IF of the 1N4000 series diode is 1A.

2. Maximum reverse operating voltage VR: refers to the maximum reverse voltage allowed to be applied across the diode. If it is greater than this value, the reverse current (IR) will increase dramatically, and the unidirectional conductivity of the diode will be disrupted, causing reverse breakdown. Usually, half of the reverse breakdown voltage (VB) is taken as (VR). For example, the VR of 1N4001 is 50V, 1N4002-1n4006 are 100V, 200V, 400V, 600V, and 800V respectively, and the VR of 1N4007 is 1000V

3. Maximum reverse current IR: It is the reverse current allowed to flow through the diode at the highest reverse operating voltage, and this parameter reflects the unidirectional conductivity of the diode. Therefore, the smaller the current value, the better the quality of the diode.

4. Breakdown voltage VB: refers to the voltage value at the sharp bend point of the diode's reverse volt ampere characteristic curve. When the reverse is a soft characteristic, it refers to the voltage value under the given reverse leakage current condition.

5. Maximum operating frequency fm: It is the highest operating frequency of the diode under normal conditions. Mainly determined by the junction capacitance and diffusion capacitance of the PN junction, if the operating frequency exceeds fm, the unidirectional conductivity of the diode will not be well reflected. For example, the fm of the 1N4000 series diode is 6.3kHz. There are also fast recovery diodes used for rectifying high-frequency AC power, such as in switching power supplies.

Reverse recovery time trr: refers to the reverse recovery time under the specified load, forward current, and maximum reverse transient voltage.

6. Zero bias capacitor CO: refers to the sum of the capacitance of the diffusion capacitor and the junction capacitor when the voltage across the diode is zero. It is worth noting that due to manufacturing process limitations, even diodes of the same model have significant parameter variability. The parameters given in the manual are often within a range, and if the testing conditions change, the corresponding parameters will also change. For example, the IR of the 1N5200 series silicon plastic encapsulated rectifier diode measured at 25 ° C is less than 10uA, while at 100 ° C, the IR becomes less than 500uA.

The method of using a multimeter to check the quality of high-voltage rectifier diodes is as follows:

1. When measuring with diode mode or high resistance mode (10k), it should be conductive or able to measure resistance. Connecting a reverse high-voltage rectifier diode in series with a resistor allows the rectifier diode to withstand high voltage. Use a multimeter to measure the resistance voltage.

2. A rectifier diode is a semiconductor device that converts alternating current energy into direct current energy. Usually it contains a PN junction with two terminals, positive and negative. The most important characteristic of a diode is its unidirectional conductivity. In a circuit, current can only flow in from the positive pole of a diode and out from the negative pole.

Measure with a diode or high resistance mode (above 10k) in the forward direction. Normally, it should be conductive or able to measure resistance. In the reverse direction, a high-voltage rectifier diode can be connected in series with a resistor and then connected to the rectifier diode to withstand a high voltage. Use a multimeter to measure whether there is voltage on the resistor (i.e. whether the diode has reverse current). If it can conduct in the forward direction but not in the reverse direction, it is good. If there is leakage or breakdown in the reverse direction, it is not good.

Through the above content, everyone has gained a certain understanding of high-voltage rectifier diodes. When the performance deteriorates, it may cause slow heating or fuse burning faults. A bidirectional protection diode is just an overvoltage protection device. When the voltage applied to the magnetron is too high due to some reason, this protection diode will break down and short-circuit, which is equivalent to a transformer output short circuit. The primary current will increase significantly, burning out the input fuse and achieving the purpose of protection.