How to use a multimeter to judge the quality of the transformer?
1) Using the resistance gear of the multimeter, you can measure whether the wire package of the transformer is broken. You can also roughly test whether the wire package and the iron core are short-circuited.
2) After the rough test, you can try connecting the transformer to the power supply. If the transformer is quickly heated after connecting to the AC power supply, it means that there is a short circuit between turns.
3) In the case of secondary open circuit (no-load), the primary current (no-load current) of the transformer should be smaller (this is related to the capacity of the transformer), the smaller the quality of the iron core, the better.
That is, with a multimeter and power-on, you can roughly judge the quality of the transformer.
Of course, this only refers to the general household small power transformer.
If you must use a multimeter to judge the quality of the transformer, there is only one way: power on and measure the voltage!
Just kidding, a multimeter can't measure the quality of the transformer, it can only measure the DC resistance of the transformer, and the quality of the transformer cannot be judged by its DC resistance alone, you have to use it Shake the table to fit and measure the insulation.
