After the transformer transformer, after the rectification and filtering, with the three-end regulator lm7812, lm7824 after voltage regulation, you can get 12v or 24v DC voltage, see how much power you use, optional larger power chip. Electronic market to sell switching power supply, you can choose a switching power supply according to voltage, frequency, power directly applied. There are also AC\/DC modules, you can directly choose one to use.
The red line of this power supply belongs to the 24 volt positive electrode, and the yellow line belongs to the 12 volt positive electrode, and the electrical appliance connecting the yellow line and the black line is 12 volts. There's 24 volts between the red and black lines.