Re: Cap calculations

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mark Broker by way of Terry Fritz <twftesla-at-uswest-dot-net>" <broker-at-uwplatt.edu>


>
>
> Hello. I have a major problem. For one of my experiments I need to know the
> exact capacity of a cap consisting of two big allumininum plates with air
> between them.
> The only known variables are the size of the plates and the distance between
> them which I want to transfer into farads. 

>From my physics notes:  C (in Farads) = (A / d) * 8.854*10^-12 *
dielectric_constant

Or, you could measure it with a meter.  Many DMMs these days can measure
capacitance.


>
> Furthermore I want to know the definition of one farad. Someone told me it is
> the capacity of two plates sized one square meter and placed at one meter
> distance. Is this true ? 

No.  A 1 Farad parallel plate cap seperated by air is roughly two 10,000 sqaure
meter plates spaced .001 meters apart.


>
> Oh,  and one more thing: please make your calculations in cm and mm because I
> am European and do not work with inches. 

One inch is exactly 2.54 cm.


Mark B.