[SATLUG] Home network

Geoff geoff at w5omr.shacknet.nu
Mon Apr 14 09:12:53 CDT 2008


Jonathan Hull wrote:
> Whoopse, I just realise I said the wrong thing about calculating
> wattage. Do Amps * Volts. Not Volts / Amps. Heh.
>
> So if amp-meter says .5, it is 110v * .5a = 55w.

In the world of Electronics, the symbol for Current is "I" (measured in 
Amperes, or Amps.)
For Power, it's "P" (measured in Watts)
The Electromotive Force, or Voltage is depicted by an E. (later 
text-books have changed this to "V" for Volts, but change is slow to 
occur in the more 'seasoned' electronics people.

So, with P for Power, I for current, and E for Volts, figuring power is 
as easy as PIE, or...

P=I*E

For a Ham Radio operator who builds his own transmitting equipment (such 
as myself) this formula is used to the extent of where it's simply 
second nature to know that
if there were 2000 volts on the plates of a pair of tubes, that were 
drawing/consuming 500mA (half of an amp) that the wattage would be 1,000 
watts.

It's just as easy if you were only using 12v on a solid state device, 
that was drawing somewhere in the neighborhood of 83 amps.  Pretty close 
to the same power consumption.

-- 
73 = Best Regards,
-Geoff/W5OMR




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