# Re: units of measurement

• To: tesla-at-pupman-dot-com
• Subject: Re: units of measurement
• From: Terry Fritz <twftesla-at-uswest-dot-net>
• Date: Mon, 16 Aug 1999 23:04:36 -0600
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

```Hi Tabraze,

Farads are a measure of how much energy a capacitor can store.  A
capacitor is much like a rechargeable battery.  If you put a voltage across
it, it sucks current and stores a given amount of energy.  This energy can
then be released suddenly as we do in a Tesla coil's primary circuit.  We
always talk on the order of nano (10^-9) (nF) Farads here.  The energy in
Joules of a capacitor is E = 1/2 x C x V^2.  The Farad is usually just the
symbol "F".

A "Henry" is a measure of inductance.  A coil has an inductance that
stores energy as current instead of voltage (as a capacitor does).  The
energy in Joules of an inductor is J = 1/2 x L x I^2.  The Henry is usually
just the symbol "H".  We usually use thousands of a Henry (mH) in Tesla
coil ranges...

Basically, capacitors store energy as voltage and inductors store energy as
current.

It can all get MUCH more complex that this but these are the basics...
There are many electronics books around that talk of this and I encourage
you to look for them.  They can explain all this in far better detail and
skill than I can here.

However, just remember that Farads are a measure of how big capacitors are
and Henrys are a measure of how big inductors (coils) are...

Cheers,

Terry

At 07:42 PM 8/15/99 +0100, you wrote:
hi,
I'm a beginner in the field of Tesla coils, I'll be 17 in October. I