What is the difference between a switching power supply and a transformer? Radio, Walkman, generally use switching power supply or transformer?

Switching power supply and traditional power supply, compared with small power consumption, high efficiency, small size, light weight, wide range of voltage regulator, etc., widely used in computers and peripherals, communications, automatic control, household appliances and other fields.

But the outstanding shortcomings of the switching power supply is to produce a strong electromagnetic interference, interference signal has a wide frequency range, but also has a certain amplitude, by conduction and radiation will contaminate the electromagnetic environment, communication equipment and electronic products cause interference. If not properly handled, the switching power supply itself will become a source of interference.

Traditional transformer power supply, the disadvantage is that the volume of heavy, low efficiency, but the current market manufacturers in order to pursue profits, are the use of poor-quality selenium steel sheet or false, resulting in overheating of the transformer, the efficiency of the even lower

Radio, Walkman, the production of the power supply is now generally used in the switching power supply, the volume of the small, most of the previous transformer voltage converter is used, low efficiency, large size