Use the digital multimeter to measure the leakage voltage. Use the AC voltage range of the digital multimeter to measure the leakage voltage of the electric soldering iron. When measuring the leakage voltage of the soldering iron with the AC voltage range of the digital multimeter, you should first adjust the digital multimeter to the AC voltage range (the digital multimeter with automatic range change is used in the figure), and then use one test lead to touch the tip of the soldering iron, and the other test lead. Contact the ground wire (or the earth), then the AC voltage displayed by the multimeter is the leakage voltage. If the soldering iron is not grounded, the soldering iron tip will have a higher leakage voltage at high temperatures. The ground end of the electric soldering iron plug is round, and the general socket cannot be inserted (the universal five-hole socket can be inserted), so the ground end of the plug is cut off. Although the socket has a ground wire, the soldering iron is not grounded, so it shows leakage voltage. During the test, the red test lead is connected to a screw through a small piece of solder wire, and this screw is connected to the ground wire of the socket on the production line. In the above figure, the measured leakage voltage is 42.51V. It can be seen that the leakage voltage of the ungrounded electric soldering iron is still high at high temperature. When the soldering iron is not connected to the power supply, the AC voltage displayed by the multimeter is only 20.9mV. When the electric soldering iron is not connected to the power supply, the AC voltage displayed by the multimeter is only 20.9mV. This reading is the interference signal of the AC voltage gear, and the number is constantly jumping. It can be seen that the ground end of the temperature-adjusting soldering iron plug has been cut off.
Use a digital multimeter to measure the leakage current, and use the AC current file of the digital multimeter to measure the leakage current of the electric soldering iron. When using a digital multimeter to measure the leakage current of electrical equipment, first adjust the multimeter to the AC current gear (if it is a multimeter that does not automatically change the range, adjust the range switch to the minimum AC current gear), and then connect the red and black test pens according to the above method. The reading displayed by the multimeter is the leakage current. In the figure above, the leakage current of the soldering iron is shown to be 5.4µA. By the way, although the leakage voltage and current measured by the above method are not necessarily very accurate, they can still be used for leakage measurement of general electrical equipment.
