Re: Power Measurent: Watts Vs. Volts

On 8/11/05 12:57 PM, in article
1123790276.708092.3420@xxxxxxxxxxxxxxxxxxxxxxxxxxxx, "tlbs"
<tlbs101@xxxxxxxxxx> wrote:

> Batteries are rated by their terminal voltage AND by their capacity,
> measured in Amp-Hours. Many AAA, AA, C, D cells have their capacity
> printed on the side, as well as their terminal voltage. Since the
> terminal voltage is known, and the capacity is known, the total
> available energy is also known (Volts x Amps x seconds = energy, in
> Joules). This is a simplistic answer -- the actual available energy
> is different from V x Capacity x time, because the terminal voltage
> drops with: current draw, rate of current draw, time, temperature, and
> other environmental factors.
>
> The rate at which you can draw that energy (Watts) from a battery is
> also more complex -- if you need to know that you should consult the
> manufacturer's data sheets. Automobile batteries list their "cold
> cranking Amps" -- that is a pretty good indicator of how much power you
> can draw from it (CCA x V).
>
> In measuring radio emmision energy, the measurement is the electric
> field strength. The units are Volts/meter (or microVolts/meter).
> Power in free space is measured in Watts/meter^2.
>
> Only when the RF energy is converted to RF current through an antenna,
> can direct power be measured. Then other factors must be taken into
> account: antenna impedance, antenna gain, antenna type. For a given
> field strength different power levels may be obtained depending on the
> antenna.
>
Are you just ranting or responding to a post? It's hard to tell when you
don't quote anything (such as above).

Go away and read up on board etiquette.

.