A linear power supply first transforms AC power through a transformer, and then rectifies and filters it through a rectifier circuit to obtain an unstable DC voltage. To achieve high-precision DC voltage, the output voltage must be adjusted through voltage feedback. From the perspective of main performance, this power supply technology is very mature, can achieve high stability, has very small ripple, and does not have the interference and noise that switching power supplies have. The voltage feedback circuit operates in a linear state, with a certain voltage drop on the adjustment tube. When outputting a large working current, the power consumption of the adjustment tube is too high, resulting in low conversion efficiency.

2, The principle of linear power supply: Linear power supply mainly includes power frequency transformer, output rectifier filter, control circuit, protection circuit, etc. Linear power supply is a type of power supply that first transforms AC power through a transformer, then rectifies and filters it through a rectifier circuit to obtain an unstable DC voltage. In order to achieve high-precision DC voltage, it is necessary to adjust the output voltage through voltage feedback. This type of power supply technology is mature, can achieve high stability, has minimal ripple, and does not have the interference and noise of switch mode power supply. However, its disadvantage is that it requires a large and bulky transformer, and the volume and weight of the required filtering capacitors are also quite large. Moreover, the voltage feedback circuit operates in a linear state, and there is a certain voltage drop on the adjustment tube. When outputting a large working current, the power consumption of the adjustment tube is too high, the conversion efficiency is low, and a large heat sink needs to be installed. This type of power supply is not suitable for the needs of computers and other devices, and will gradually be replaced by switch mode power supplies. 3, Compared to switching power supplies: Switching power supplies mainly include input grid filters, input rectifier filters, inverters, output rectifier filters, control circuits, and protection circuits. Their functions are:

1. Input power grid filter: Eliminates interference from the power grid, such as starting of motors, switching of electrical appliances, lightning strikes, etc., while also preventing high-frequency noise generated by switching power supplies from spreading to the power grid.

2. Input rectifier filter: Rectify and filter the input voltage of the power grid to provide DC voltage to the converter.

3. Inverter: It is a crucial part of a switching power supply. It converts DC voltage into high-frequency AC voltage and plays a role in isolating the output part from the input power grid.

4. Output rectifier filter: Rectify and filter the high-frequency AC voltage output by the converter to obtain the required DC voltage, while also preventing high-frequency noise from interfering with the load.

5. Control circuit: Detect the output DC voltage, compare it with the reference voltage, and amplify it. Modulate the pulse width of the oscillator to control the converter to maintain stable output voltage.

6. Protection circuit: When the switching power supply experiences overvoltage or overcurrent short circuit, the protection circuit stops the switching power supply from working to protect the load and the power supply itself.