How to detect the quality of high voltage diodes

　　When testing high-voltage diodes, you can use the multimeter's R×10k range to measure its forward and reverse resistance values. For normal high-voltage diodes, its forward resistance value is greater than 200kΩ, and its reverse resistance value is infinite. If it is measured that both its forward and reverse resistance values ​​have certain values, it means that the high-voltage diode has been soft-broken and damaged.

　　Semiconductor diodes are also called crystal diodes, or diodes for short; they are electronic components that transmit current in only one direction. They are devices with two terminals connected by one part number, and have the property of making current flow or not flow according to the direction of the applied voltage.

　　Semiconductor diodes are used in almost all electronic circuits. They play an important role in many circuits. They are one of the earliest semiconductor devices and are widely used.

　　The tube voltage drop of the diode: the forward tube voltage drop of the silicon diode (non-luminous type) is 0.7V, and the forward tube voltage drop of the light-emitting diode varies with different luminous colors.

　　What is the difference between a high-voltage diode and a high-voltage silicon stack? How to detect whether a high-voltage silicon stack is good or bad?

　　The silicon stack is a series of diodes that are packaged. The high-voltage silicon stack is composed of multiple high-voltage rectifier diodes (silicon particles) connected in series. When testing, the forward and reverse resistance values ​​can be measured with the R×10k range of the multimeter. For a normal high-voltage silicon stack, its forward resistance value is greater than 200kΩ, and its reverse resistance value is infinite. If a certain resistance value is measured in both the forward and reverse directions, it means that the high-voltage silicon stack has been soft-broken and damaged.

　　Another method is: the high-voltage silicon stack has a rectification function. After the multimeter range switch is turned to the DC voltage range of 250V or 500V, the high-voltage silicon stack is connected in series and connected to the 220V AC power supply as shown in Figure 1d. Due to the rectification effect of the high-voltage silicon stack, the deflection of the multimeter pointer reflects the average current after half-wave rectification, so the high-voltage silicon stack and the multimeter constitute a half-wave rectification AC voltmeter.

　　When the high-voltage silicon stack under test is connected in the forward direction, the multimeter reading is qualified when it is above 30 V. When connected in the reverse direction, the multimeter pointer should deflect in the reverse direction. If the multimeter pointer does not move, it may be that the high-voltage silicon stack is short-circuited, so that the current cannot pass through the multimeter, but it may also be that the high-voltage silicon stack has broken down. Although the AC voltage can be directly applied to the multimeter during a short circuit, the multimeter pointer does not have time to swing because the AC frequency is 50 Hz, so the multimeter with the range switch set to the DC voltage position is always at zero.

　　Therefore, to determine whether the high-voltage silicon stack is short-circuited or open-circuited, just turn the multimeter's range switch to the AC voltage 250 V or 500 V. If the reading is 220V AC voltage, it proves that the high-voltage silicon stack being tested is short-circuited. If the reading is zero at this time, it indicates that the high-voltage silicon stack is open-circuited.