Pre-rectified voltage in?

Thread Starter

LikeTheSandwich

Joined Feb 22, 2021
151
So, for something relatively simple, like a power tool battery charger (simple compared to medical equipment or an oscilloscope at least), what would most likely happen if I sent in a pre-rectified DC voltage? I know that transformers requires AC, so assuming no transformer, what would probably happen? Are there any discrete components that need AC, that might get damaged or blow up or something if I give it DC?
 

Ian0

Joined Aug 7, 2020
5,188
Most small power supplies these days are switched-mode, so the first component encountered is a rectifier to create a 325V*DC bus.
So, supplying it with 325V DC will work just fine.

A few provisos:
Supplying DC only uses two diodes in the bridge, so if the manufacturer is running them really close to the limit, they might overheat.

Some supplies have a voltage doubler to create 325V from a 115V AC supply, they really do need AC to work.

Some supplies have a PFC circuit. That is simply a boost converter to produce 400V DC from any AC voltage input. Most configurations I know of would work with DC, but there may be variants of the circuit that really do need AC, that I don’t know about.

*325V Dc is 230V AC rectified. If you have 110V-120V AC it will be different.
 
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