Working principle: Linear power supply first reduces the voltage amplitude of alternating current through transformer, then rectifies it through rectifier circuit to get pulse DC, and then filters it to get DC voltage with tiny ripple voltage. To obtain high-precision DC voltage, it must be stabilized by voltage stabilizing circuit.
The working principle of switching power supply is that the input end directly converts the rectified electric energy into alternating current, and then under the action of high-frequency circuit oscillation, the switch controls the on-off of current to form high-frequency pulse current. With the help of inductor, stable low-voltage DC is output.
Efficiency: Linear power supply has low efficiency, and there are iron loss and copper loss in its working process, and the efficiency is generally 50%-60%. In contrast, switching power supply has high efficiency, and there is no iron loss and copper loss in its working process, and the efficiency is generally 80%-90%.
Dimensions: Linear power supply usually needs large transformers and radiators, so it is huge. On the contrary, switching power supply uses high-frequency switch to realize voltage conversion, and the required transformer can be made smaller, so the volume is smaller.
Stability: Linear power supply usually has better stability and lower noise level, without high-frequency noise and switching interference existing in switching power supply. However, the switching interference of switching power supply is large, so special measures need to be taken to reduce the interference.
Cost: The cost of switching power supply is higher than that of linear power supply, and the manufacturing cost of switching power supply is higher, which requires higher technology and equipment. Linear power supply is usually simple and relatively low cost.