1. Use a multimeter to measure the resistance value of two wires. Two wires with high resistance value are connected to 220V and those with low resistance value are connected to 12V.
For most of these voltage regulators, there is a group of terminals on the power side and several groups of 36v24v12v outgoing lines on the low voltage side. After the power supply can be connected, use a multimeter at the low-voltage side to measure the indicated voltage as 12V, and then connect the wiring terminal.
2. Use the multimeter to connect to a lower resistance gear, such as rx1 or rx10. One group is connected in pairs, and then measure the resistance value. The group with larger resistance value is the input terminal, connected to 220V.
If the winding of the transformer can be seen, the one with smaller wire diameter is connected to the input.
3. 220V to 12V transformers are generally red line input and black line output, but they will be different from different manufacturers. In this way, you can see the label on the transformer, which will specify the input voltage, input lead color, output voltage and output lead color of the transformer in detail. If you are not sure, you can also ask the manufacturer during wiring.
Editor: hfy (the article is integrated from Baidu)