How does a power surge cause damge to a PC?

[Asnrefugee]

Anyone got detailed info on this? I'm just curious of how it happens to destroy your PC. Any detailed info out there?

 

[AWhackWhiteBoy]

uuhhh,heh,are you seious? it puts too much power to the pc parts,past their ratings,and they die. very simple.

 

[Matthias99]

An incredibly detailed and informative response there...

By 'power surge' people generally mean a voltage spike -- a short-term event where the normal supply voltage (120VAC in the US) goes above (potentially WAY above) normal. In the event of a lightning strike on a nearby power line (one of the more extreme events that can happen), the supply voltage might temporarily (for a few milliseconds, at least) be up in the hundreds of thousands of volts. The power supply in your computer is supposed to 'buffer' the internal rails from fluctuations in the external power lines. However, in such extreme circumstances, it often can't keep up, and the internal rails will often *also* spike (although not to quite such extreme voltages). By Ohm's law (V=IR), if you increase the voltage feeding a fixed-resistance circuit, the current (amps) flowing through the circuit will increase proportionally. This can be very damaging to the silicon logic gates used in computers, for complex subatomic physics reasons that I don't fully understand myself. Other components (such as voltage regulators, capacitors, etc.) also do not take kindly to such mistreatment. And if the voltage gets REALLY high, you can actually short across paths within chips, or even through PCB layers, physically destroying the circuits involved.

 

[Maximilian]

To feel what your pc feels during a surge put your finger into an electrical socket, and thats how it gets damaged.

 

[Mday]

Originally posted by: Asnrefugee
Anyone got detailed info on this? I'm just curious of how it happens to destroy your PC. Any detailed info out there?

There are two things involved with electrical power: voltage and current. A spike can come in either form, but it's typically voltage unless your house gets struck by lightning. With a voltage spike the wires or traces inside your system becomes too high. Since you can consider them as capacitors, a high voltage means the capacitors just got discharged across the dielectric (insulation). The discharge causes several forms of damage some of which are: short circuits, current spikes, blown traces which are all physical damage to the system. As stated before, a current spike can happen outside of the voltage spike but is usually a side effect (as opposed to direct) of what the power problems are. With a current spike, a higher than desired current is sent through a wire. This causes the wire to overheat and burns to appear on your system (wires or circuit board). Typically, a voltage spike causes a current spike which causes the pop and hiss and burning smell you notice in burnt electronics.