For the contact resistance test and wiring method of D-SUB connector, we need to start with the basic concepts. D-SUB connector is a type of connector commonly used in electronic devices, which can transmit signals and power. When using this connector, we need to perform contact resistance test to ensure good and stable connection.。

Contact resistance refers to the resistance between the two metal contact surfaces of the connector joint. The purpose of contact resistance test is to judge the contact quality of the connector. If the contact resistance is too large, it will cause problems such as unstable signal transmission, heat generation and increased power consumption. Therefore, contact resistance test is very important. Commonly used test methods include DC voltage method and AC current method.

DC voltage method is a simple and intuitive test method. During the test, we need to apply a certain amount of current through two electrodes and measure the voltage drop. By calculating the ratio of current to voltage, the size of the contact resistance can be obtained. This method is suitable for low-frequency signal transmission and high-current transmission scenarios.

AC current method is a more accurate test method. This method measures the contact resistance by applying an AC current of a certain frequency and amplitude. Since the frequency of the AC current changes continuously, a more accurate contact resistance value can be obtained. This method is suitable for high-frequency signal transmission and low-current transmission scenarios.

When conducting contact resistance tests, we also need to pay attention to choosing the right wiring method. The wiring method refers to the connection method between the connector pins. Common wiring methods include direct plug-in, and printed.

The direct plug-in wiring method is to insert the pins of the connector directly into the slots on the connector seat. This wiring method is simple and convenient, and is suitable for frequent plugging and unplugging and easy replacement scenarios. However, when transmitting high-frequency signals, the direct plug-in wiring method will introduce additional inductance and capacitance, affecting the signal transmission quality.

The wiring method is to connect the pins of the connector to the pads on the printed circuit board. This wiring method can achieve more stable signal transmission and can provide better electrical performance. However, the ** wiring method is not suitable for frequent plugging and unplugging and easy replacement scenarios because hot melt connection is required.

The printed wiring method is to connect the pins of the connector to the wires on the printed circuit board. This wiring method is suitable for complex circuit board designs and can achieve higher signal transmission rates and more stable connections. However, in the printed wiring method, special manufacturing processes and higher costs are required.

In short, the contact resistance test and wiring method selection of D-SUB connectors are important links to ensure the quality of connectors and stable signal transmission. By using appropriate testing methods and selecting the best wiring method, the reliability and transmission performance of the connector can be improved.