In almost all electronic circuits, semiconductor diodes are used. It plays an important role in many circuits. It is one of the earliest semiconductor devices and its applications are also very extensive. How much do you know about high-voltage rectifier diodes? The series of high-voltage rectifier diodes are high-voltage rectifier devices composed of multiple micro-unit PN junction chips doped with special metals, using a combination of unique technology and embedded heat dissipation patented technology, to achieve a layered unit structure that can withstand high voltage and large current. What are the main parameters of high-voltage rectifier diodes? How to detect the quality of high-voltage rectifier diodes? Let's take a look with the little goo.
The main parameters of high-voltage rectifier diodes:
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. It should be noted that the average current through the diode cannot be greater than this value, and the heat dissipation conditions should be met. For example, the IF of 1N4000 series diode is 1A.
2. Maximum reverse working voltage VR: refers to the maximum allowable reverse voltage applied across the diode. If it is greater than this value, the reverse current (IR) will increase sharply, and the unidirectional conductivity of the diode will be destroyed, causing reverse breakdown. Usually take half of the reverse breakdown voltage (VB) as (VR). For example, the VR of 1N4001 is 50V, the VR of 1N4002-1n4006 is 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 under the highest reverse working voltage. This parameter reflects the quality of the unidirectional conductivity of the diode. Therefore, the smaller the current value, the better the diode quality.
4. Breakdown voltage VB: refers to the voltage value at the sharp bend point of the reverse volt-ampere characteristic curve of the diode. When the reverse is a soft characteristic, it refers to the voltage value under a given reverse leakage current condition.
5. The highest operating frequency fm: It is the highest operating frequency of the diode under normal conditions. It is 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 1N4000 series diode is 6.3kHz. In addition, fast recovery diodes are used in the rectification of higher frequency alternating currents, such as switching power supplies.
Reverse recovery time trr: refers to the reverse recovery time under the specified load, forward current and maximum reverse transient voltage.
7. Zero-bias capacitance CO: refers to the sum of the capacitance of the diffusion capacitance and the junction capacitance when the voltage across the diode is zero. It is worth noting that, due to the limitation of the manufacturing process, even the same type of diode has a large dispersion of its parameters. The parameters given in the manual are often within a range. If the test conditions change, the corresponding parameters will also change. For example, the IR of 1N5200 series silicon plastic rectifier diodes measured at 25°C is less than 10uA, while at 100°C IR becomes less than 500uA.
Use a multimeter to detect the quality of high-voltage rectifier diodes as follows:
1. To use a diode gear or high resistance gear (10k) to measure the resistance, it should be turned on or can measure the resistance. The reverse high voltage rectifier diode is connected to the rectifier diode to allow high voltage resistance. Use a multimeter to measure the resistance voltage (that is, whether the diode reverse current). It can conduct and reverse leakage or breakdown.
2. The rectifier diode is a semiconductor device that converts AC power into DC power. Usually it contains a PN junction with two terminals, a positive electrode and a negative electrode. The most important characteristic of a diode is its unidirectional conductivity. In a circuit, current can only flow in from the anode of the diode and flow out of the cathode.
Use diode gear or high resistance gear (above 10k) to measure in the forward direction. Normally, it should be turned on or the resistance can be measured. In the reverse direction, connect the high voltage rectifier diode with series resistance followed by the high voltage allowed by the rectifier diode. Use a multimeter to measure the resistance. Whether there is any voltage on it (that is, whether the diode has a reverse current), it is good that it can be turned on in the forward direction, and it is not good if there is leakage or breakdown in the reverse direction.
Through the above content, everyone has a certain understanding of high-voltage rectifier diodes. When the performance deteriorates, it may cause slow heating or failure of burning insurance. The bidirectional protection diode is just an over-voltage protection device. When the voltage applied to the magnetron is too high for some reason, the protection diode will break down and short-circuit, which is equal to the transformer output short-circuit, the primary current increases greatly, and the input insurance is blown. The purpose of protection. If you want to know more product information, you can enter ICGOO for inquiries.
