How to explode a power supply – and understand what’s inside it!

The one PC component that troubles entrants in our Master builder competition more than any other is the power supply. Our judges say that the selected PSUs are often underpowered or overpowered for their systems and that many system builders don’t appreciate the difference between a cheap PSU and a high quality one.

So we asked a man who lives and breathes power supplies Christoph Katzer to explain what you should look for in a PSU. German-born Katzer is the global director for the entire PSU business at Antec one of the world’s biggest components makers but agreed to put brand loyalties aside to explain how PSUs work in the videos below. But first the explosion!

Bang! What can happen when the PSU is underpowered for your system

When Katzer visited the APC office he brought with him a generic power supply he picked up for $35 in a local computer store. This cheap PSU showed 550W on its label – but it was clear that this was labelled with peak power and was not able to run 550 watts. See what happened when Katzer put it under just 75% load (400 watts only). Katzer says that the PSU component most likely to fail and cause an explosion is the PFC (Power Factor Correction) Mosfet and the most likely scenario (duplicated in this video) is when you have a PSU mislabelled with 550W. Katzer says that when PSUs are under-specced they ultimately overheat if there is too much current flowing through them.

What’s actually inside a Power Supply

Katzer goes on a tour of the internals of a power supply.

Difference between a quality PSU and a cheap generic one

In PSUs you definitely get what you pay for. There are massive differences in the quality and even number of components between a good power supply and a cheap one.

Inside a high-end power supply

So what do you get when you buy a really top-end PSU?

Difference between a good PSU and an even better one

What does a really really good power supply look like? Katzer compares a premium PSU with a very good one.


Before you buy a PSU – what to look for

Selecting a PSU that’s right for your PC is not as straightforward as it seems. Here Katzer runs through the key things to consider before purchase.