Application FAQ

Application FAQ

1. Electrical performance
The electrical properties of the junction box mainly include parameters such as working voltage, working current, and resistance. Therefore, to measure whether a junction box is qualified.

2. Working voltage
When the reverse voltage applied across the diode reaches a specific value, the tube will be broken down, and the unidirectional conductivity will be lost. Therefore, the maximum reverse working voltage value is specified to ensure safe use. For example, the reverse withstand voltage of IN4001 diode is 50V, and the reverse withstand voltage of IN4007 is 1000V. When the junction box operates under normal working conditions, the highest voltage that its corresponding device is subjected to. Currently, the working voltage of the junction box is 1000V (DC).

3. Junction temperature current
Also known as working current, it refers to the maximum forward current value allowed to pass when the diode works continuously for a long time. Because when the current passes through the tube, the die will heat up, and the temperature will rise. When the temperature exceeds the allowable limit (about 140 for silicon tubes and about 90 for germanium tubes), the die will be overheated and damaged. Therefore, the diode should not exceed the rated forward working current value of the diode in use.
When a hot spot effect occurs in the component, current flows through the diode. Generally speaking, the higher the junction temperature current, the better, so the junction box's operating range is more extensive. The junction temperature current can reach 16A, and for the minor component junction box, the junction temperature current must reach 9A.

4. Connection resistance.
The connection resistance does not have a precise range requirement but only reflects the connection quality between the terminal and the busbar.
There are two connection methods of terminal blocks, one is clamping connection, and the other is welding. Both ways have advantages and disadvantages:
First of all, the clamping connection is quick to operate and easy to maintain. Still, the primary area with the terminal is small, and the connection is not reliable enough, resulting in high contact resistance and ease of heat.
Second, the conductive area of ​​the welding method is small, the contact resistance is small, and the connection is tight. However, the high soldering temperature during operation makes it easy to burn the diode.

5. Welding strip width
The so-called width of the welding strip refers to the width of the lead wire of the component the width of the bus strip and includes the spacing between the welding strips. There are three specifications of 2.5mm, 4mm, and 6mm due to the busbar resistance and busbar spacing consideration.

6. Use temperature
The junction box works together with the components and is more adaptable to the environment. In terms of temperature, the current standard is -40 ~ 85 .

7. Junction temperature
The junction temperature of the diode will affect the leakage current in its off state. Generally speaking, the leakage current will double for every ten-degree increase in temperature. Therefore, it is necessary to use the rated junction temperature of the diode to be higher than the actual junction temperature. For example, 2AP1 type germanium diode, if the reverse current is 250uA at 25, the temperature rises to 35, the reverse current will increase to 500uA, and so on, at 75, its reverse current has reached 8mA, not only lost The unidirectional electrical conductivity will also cause the tube to overheat and be damaged.

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