“They don’t build ’em like they used to.” There’s plenty of truth to that old saw, especially when a switch-mode power supply from the 1940s still works with its original part ...

The common type of power supply used with computers and other electronic equipment. The "switching" comes from switching a transistor on and off to create square waves for input to a transformer.

A computer power ... "switching" power supplies are commonly used. Their name is derived from the type of circuit used to change the voltage. For more details, see transformer. See power adapter.