* Posts by Keith Caley

3 posts • joined 11 Jun 2014

Security guard cost bank millions by hitting emergency Off button

Keith Caley
Mushroom

Re: Why is hardware so sensitive?

The majority of electrical/electronic equipment has a 'wound component' (Inductor) somewhere in its mains input circuitry.

When current ceases to flow through said item, the magnetic field collapses rapidly, producing an EMF (the same principle is used in old tellys and monitors to produce 25KV for the CRT). So, if the power supply to the equipment is cut off the resulting EMF is fed back into the 'outside world' via the AC mains supply lead.

Now one piece of equipment on its own probably wouldn't do much harm, but when you've got a room chock full of 'em, the effect tends to add up... if not multiply :)

Another reason is electrolytic capacitors, even 'computer grade' ones, tend to dry out, and their effective internal resistance goes up, meaning that they are less able to cope with sudden surges - it's a double whammy, really.

p.s. I'm so pleased that after donkey's years of reading the register, I've finally found a question that I can answer.

Maplin shutdown sale prices still HIGHER than rivals

Keith Caley

Re: Really

..."they could be chained slaves in those warehouses for all they care."

Shades of Breaking Bad!

I am NOT a PC repair man. I will NOT get your iPad working

Keith Caley
Holmes

Re: Does this article seem familiar to you...

Well, that's only to be expected if you read the preamble at the beginning of the article: -

"Something for the Weekend, Sir? Alistair Dabbs is recovering from the dreaded lurgy, but still none too chipper this week, so we’re happy to let him linger in his bath chair and tartan blanket once again. No doubt his neighbours will be concerned though, if this repeat publication from 2013 is anything to go by." ;)

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