How to change the 12V switching power supply to adjustable output?

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How to change the 12V switching power supply to adjustable output?

Posted Date: 2024-01-17

How to change the 12V switching power supply to adjustable output?

Changing the 12V switching power supply to adjustable output requires the following steps:

1. Understand the basic principles of switching power supply

A switching power supply is an electronic device that converts alternating current into the required stable direct current. Its basic principle is to convert the input alternating current into low-voltage alternating current through a transformer, and then obtain stable direct current through circuit processing such as rectification, filtering, and voltage stabilization.

2. Determine the need for adjustable output

Before transforming a switching power supply into an adjustable output, you first need to determine the required adjustable output voltage range and current requirements. This helps us choose the appropriate regulating circuit.

3. Add voltage adjustment circuit

In order to achieve the goal of adjustable output, we need to add a voltage regulation circuit to the output end of the switching power supply. This circuit usually consists of a voltage regulator, potentiometer, feedback circuit, etc.

The voltage regulator is the core part of the circuit. Its function is to automatically adjust the output voltage according to changes in the input signal to stabilize it at the set value. Commonly used voltage regulators include linear voltage regulators and switching voltage regulators. Linear regulators are suitable for applications requiring lower noise and higher accuracy; switching regulators are suitable for high-power, high-efficiency applications.

The potentiometer is used to manually adjust the voltage output. By adjusting the resistance of the potentiometer, the reference voltage of the feedback circuit is changed, thereby changing the output voltage of the voltage regulator.

The feedback circuit is used to detect the output voltage and compare it with the set value, and adjust the output voltage by controlling the working status of the voltage regulator.

4. Conduct circuit wiring

Depending on the design of the voltage regulation circuit and the type of voltage regulator selected, we need to perform corresponding circuit wiring work. According to the circuit diagram, connect the voltage regulator, potentiometer, feedback circuit and other components.

5. Carry out power supply modification

After the circuit wiring is completed, the switching power supply is modified according to the actual situation. This may involve disassembling the switching power supply, wiring, soldering, and securing the circuit board. Always use caution and follow safe operating procedures when performing these operations.

6. Perform power supply debugging

After the power supply transformation is completed and safety is ensured, the power supply can be debugged. First, connect the adjustable output power supply to a suitable load circuit, then adjust the output voltage by turning the potentiometer. At the same time, observe the working status of the load circuit to ensure that the power output voltage is stable and normal.

7. Carry out output voltage range test

After completing the power supply debugging, the output voltage range test needs to be performed. At this time, adjust the potentiometer to change the output voltage, and use a digital multimeter or oscilloscope to measure and record the output voltage values ​​corresponding to different potentiometer positions. Use this to verify whether the power supply meets the requirements for adjustable output.


Changing the 12V switching power supply to adjustable output requires a basic understanding of the principles of the switching power supply, determining the requirements, adding a voltage adjustment circuit, performing circuit wiring and power supply modification, and finally debugging and testing. In this way, the 12V switching power supply can be successfully changed to an adjustable output.

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