Power entry modules are used in devices that have an external power source. They provide the power supply connection for a product and are typically configured as a chassis-mounted receptacle for the plug of a power cable. Power entry modules are usually subject to regulatory compliance standards for safety, EMI and noise suppression.

Power entry modules come in a number of configurations. Modules are available to mount onto panels or chassis or snap-in to a hole in the panel. Some power entry modules are PCB mounted, although consideration to stress relief is required. Varieties are available that integrate EMI filtering. Filter types and standards can change depending on the emissions regulations that are required to be met in the target market and application. Medical RFI regulations are an example of application-specific standards.

Features available also include built-in circuit breakers with or without illumination, on/off switches and dual or single fuse holders with conversion clips to convert a dual to a single if required. Voltage selectors are integrated on some models to support international mains voltage standards. There can be features to account for environmental considerations, for example ‘dust ingression’. Power adapters can have features that improve RF performance, with built-in shielding for EMI suppression and may even integrate a ground-circuit inductor to isolate an equipment chassis from power line ground at RF frequencies.

Important electrical characteristics of adapters include the rated voltage, the one-minute hipot testing (both line-to-ground and line-to-line) and the rated current. They will also have a maximum leakage current specification that must comply with the regulations of the target market.