What does a 24V power supply look like?(5)

input protection circuit
General module power products have built-in filters, which can meet the requirements of general power supply applications. If a more demanding power system is required, an input filter network should be added. An LC or π-type network can be used, but care should be taken to choose a smaller inductance and larger capacitance as much as possible.
In order to prevent the transient high voltage of the input power supply from damaging the power supply of the module, it is recommended that the user connect a transient absorption diode at the input end and use it with a fuse to ensure that the module is within a safe input voltage range. In order to reduce common-mode noise, Y (Cy) capacitors can be added, and a few nf high-frequency capacitors are generally selected. R is a fuse, D1 is a protection diode, and D2 is a transient absorption diode (P6KE series).

Regardless of how much control the product material and production process are, aging needs to be checked. Because the incoming inspection of electronic components and transformers is difficult to control, the quality stability of this batch of power supplies and whether the materials are detected to have potential safety hazards can only be detected through aging and high-temperature sampling of the entire batch of power supplies.