Russia the switching frequency of the AC-DC switching power supply module?(2)

Russia Choosing the switching frequency of the 24V input power supply does not mean choosing the switching frequency of the 24V input power supply with a good switching frequency, but the choice is suitable for your own use. Most of the current market is like this. The frequency of the AC-DC switching 24V input power supply module is between 50K and 135K, and this frequency range can meet most applications. Let's discuss it. Some of the problems that AC-DC encounters when choosing switching frequency:

(3) Before the installation is completed and the power is turned on, the wiring on each terminal should be checked and checked again to ensure that the input and output, AC and DC, single-phase and multi-phase, positive and negative, voltage and current values are correct. Prevent the occurrence of reverse and wrong connections.
(4) For high-power power supplies, there are generally two or more "+" output terminals and "-" output terminals. In fact, they belong to the same output electrode, but for the convenience of user wiring, they are connected together internally.
(5) The module power supply is not allowed to work at full load for a long time. The utilization rate of linear power supply should be controlled within 60%; the utilization rate of switching power supply should be controlled within 80%, otherwise it may cause early artificial failure of module power supply.

1. Why generally do not choose a switching frequency lower than 50K

We know that the lower the switching frequency, the smaller the switching loss, but on the other hand, with the reduction of the switching frequency, the volume of the 24V input power supply equipment will be reduced to the maximum, which is not conducive to miniaturization. When the switching 24V input power supply is working, due to the switching of the switching device, the magnetic core will vibrate, and the frequency range that the human ear can hear is about 20~20000Hz. In order to avoid audible noise, we usually choose to stay away from the 20 frequency KHz.