Archived from groups: alt.comp.hardware,alt.comp.hardware.pc-homebuilt,uk.comp.homebuilt,alt.comp.hardware.homebuilt (
More info?)
VWWall <vwall@DEADearthlink.net> wrote:
> Regal wrote:
>> I read on some website that the capacitors in a PC's PSU can
>> hold a charge for long after they have been switched off and
>> that the charge could be fatal.
>>
>> Is this really so? Surely that is exaggerating?
>
> The capacitors in the input circuit of a PC PSU are charged to
> ~320 V DC. This can, indeed, be lethal, but they are shunted
> by bleeder resistors which will reduce the voltage to a safe
> value in a minute or two. By the time you get the unit out of
> the computer case and remove it's cover, the voltage is
> probably safe. To be sure, wait five minutes after unplugging
> the PSU before touching anything inside.
>
> A PC monitor uses high voltage, (up to 25,000 V), on the CRT.
> The tube glass envelope is used as a capacitor, and can hold a
> charge for some time. Because the energy content is quite
> low, contact with this very high voltage is usually not
> deadly, but may result in serious injury from muscle reaction.
> Don't remove the housing from a CRT monitor unless you
> understand how to safely discharge this voltage!
Thinkingof power supplies ...
if a faster processor needing extra power was installed (say, it
needs an extra 30 W) then would that noticeably reduce the life of
the power supply?