Re: Re: Power supply question.....

Hi,

It would be a wonderful world if capacitors were capacitors,
resistors were resistors and inductors were, well, inductors.

In a perfect world they are, but not in this one.

The reality is capacitors have a little bit of resistance and
inductance, rresistors have a little bit of capacitance and
inductance, inductors have.. you see where I'm going with this.

Capacitors have, unfortunately, some series resistance which causes a
lot of problems. When a capacitor carries a lot of current due to a
varying voltage across it (it's what they are supposed to do), that
current passes thru a equivalent series resistance (ESR). Just like
any current passing thru a resistance, it creates heat, specifically
to the tune of W = I squared R. Since "R" is inside the capacitor,
the capacitor gets hot if "I" is large.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> JanRwl@A... wrote:

. What school of electrical engineering says that
> capacitors "run hot"? I was always taught that a capacitance
neither "uses"
> nor "supplies" energy! Ah, well . . . Perhaps things have changed
since
> I was a student.