How do you test the resistance of an electric soldering iron?
Electric soldering iron is an essential tool for electronic production and electrical maintenance, mainly used for welding components and wires. It can be divided into internal heating electric soldering iron and external heating electric soldering iron according to mechanical structure. According to function, it can be divided into non suction soldering iron and suction soldering iron. According to different uses, it can be further divided into high-power soldering iron and low-power soldering iron.
The electric soldering iron test includes three parts: grounding resistance test (cold/hot state), leakage voltage test, and leakage current test.
1. Grounding resistance test of electric soldering iron in cooling state:
In the absence of power, connect one end of the multimeter probe to the ground terminal of the power plug and the other end to the tip of the soldering iron to test the data;
2. Ground resistance test of electric soldering iron under heating state:
Plug in the power, turn on the soldering iron, and connect one end of the multimeter probe to the ground terminal of the socket, while the other end contacts the test board that is in contact with the soldering iron. Measure the result;
3. The leakage voltage test and leakage current test of an electric soldering iron are similar to the resistance test method. It should be noted that the multimeter needs to switch gears or adjust the position of the multimeter probe wire when measuring current.
How to choose an electric soldering iron?
(1) When welding integrated circuits, transistors, and components that are prone to thermal damage, consider using a 20W internal heating or 25W external heating soldering iron.
(2) When welding thicker wires or coaxial cables, consider using a 50W internally heated or 45-75W externally heated soldering iron.
(3) When welding larger components, such as metal chassis grounding pads, an electric soldering iron of over 100W should be used.
(4) The shape of the soldering iron head should adapt to the surface requirements of the welded part and the assembly density of the product.
Simply put, the power and type of electric soldering iron should be reasonably selected based on the welding object. If the workpiece to be welded is large, the power of the electric soldering iron used should also be higher. If the power is low, the welding temperature is too low, the solder melts slowly, the flux is not easy to evaporate, the solder joints are not smooth and firm, which will inevitably result in unqualified appearance quality and welding strength, and even the solder cannot melt, making welding impossible. However, the power of the soldering iron should not be too high. If it is too high, it will transfer too much heat to the welded parts, causing the solder joints of the components to overheat, which may cause damage to the components, causing the copper foil of the printed circuit board to fall off, and the solder to flow too fast on the welding surface, which cannot be controlled.
