What's a switching power supply?

[Szech]

I've seen this term quite a bit, and I don't know what it means.

[alondra]

just a guess but may be reference to automatic shutdown, my new box shuts down with out touching a switch, something on the MOBO does it
Al

[dkozloski]

A switching power supply reduces line voltage (115v) to lower voltages (+5v, +12v) by switching the current on and off at a high rate. A longer on vs. off period gives a higher voltage output. A shorter on vs. off period gives a lower voltage. Because of the way this is done with newer solid state devices, this is a highly efficient process.
In previous years this voltage reduction was done with heavy, expensive, and inefficient transformers with analog power supplies.
The down side to switching power supplies is that they can introduce electronic noise into the power grid that is quickly becoming a problem for power companies.

[This message has been edited by dkozloski (edited 05-18-2000).]

[alondra]

Hmmm maybe this is why my new box causes a howl in my radio (AM) others didn't.?