Some switched mode power supplies start by rectifying the mains voltage to 350+volts dc and storing this on a capacitor.That is enough to kill you in certain circumstances.All capacitors from main powered equipment should be treated with respect. Ken Reynolds |
Capacitors in PSU are dangerous?
"Regal" wrote in message
... 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? Isn't that CRT monitors not PC PCUs? -- Niel Humphreys |
Niel Humphreys wrote:
"Regal" wrote in message ... 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? Isn't that CRT monitors not PC PCUs? Both. They're used in the AC-DC transformer. -- Paul |
"Regal" wrote in message ... 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? No they are serious, I had the Unfortunate experience not too long ago of puncturing one on accident. Nasty little shock, let me tell ya. Some nice electrical burns as well. |
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? You sould check the PSU with a stroboscope before opening it. -- ThePunisher |
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! Virg Wall -- It is vain to do with more what can be done with fewer. William of Occam. |
"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? A well-designed power supply has bleed resistors across the big capacitors (usually the filtering electrolytics) and the charge should be essentially dissipated within seconds, certainly a minute, of shutdown. As for a "fatal" charge, what's the maximum voltage used in a PC - 12 volts for the fans? Bottom line - have you ever seen a "Danger! High Voltage" warning on a PC case? *TimDaniels* |
|
"ThePunisher" 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? You sould check the PSU with a stroboscope before opening it. Eh? Tim -- Love is a travelator. |
"Tim Auton" tim.auton@uton.[groupSexWithoutTheY] wrote in message
... "ThePunisher" 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? You sould check the PSU with a stroboscope before opening it. Eh? Tim -- Love is a travelator. The stroboscope is effective only as long as the PSU is spinning or vibrating rapidly. Or if you are hallucinating that it is... -- John McGaw [Knoxville, TN, USA] http://johnmcgaw.com |
All times are GMT +1. The time now is 03:30 AM. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
HardwareBanter.com