Kevin, Very well put, now I can understand that concept. Never thought to take the voltage into consideration. You never know until you ask, tis how we always learn.
Mathew --- In Repeater-Builder@yahoogroups.com, Kevin Custer <[EMAIL PROTECTED]> wrote: > > n9lv wrote: > > Mike, I am on old TV radio/tech repair for RCA and Zenith, so > > understandig the voltage is not the question I had. What I am > > refereing to, is take for example, I have a 200 watt amplifier that > > came from the factory with 6 guage wire on it, much like the kids > > that is buying the 4 guage wire to run the 200 watt class D amps for > > the deep sub, were talking about how they accomplish 1/2 KW with all > > small wires. You would not wire your 220 amp with such small wires. > > I'm just curious how they can handle the amps with such small wires. > > Where is the big leads. Example, to the 10 watt exciter, they have > > 12 guage wires, why would they not have something like that going to > > such a high voltage amp. Thats is all that I am curious about. Much > > like the 35kv carrier for a tube was 14 guage wire with a heavy > > insulator around it. > > Power is derived from two main things, voltage and current. Power > expressed in mathematics is simple - voltage is multiplied by the > current. V times A. > When you have lower voltage, like 12 volts in a vehicle, to create big > power you must have (draw) big current - many amperes. A typical 200 > watt per channel audio amplifier will draw about 600 watts of DC power. > Okay, we'll work the law backwards since we know the voltage and the > power consumption. 600 (watts) divided by 12 (volts) is 50 amperes. No > big wonder why the kids want (need) #6 or #4 wire size. > > Now lets take my 4EF5A1 330 watt RF power amplifier. It's a little > better than 50% efficient, so to make 330 watts of RF it consumes about > 600 watts of power at the tube, just like the kids audio amp. However, > it has 2000 volts on the plate, not 12 volts, so lets do the math... > 600 (watts) divided by 2000 (volts) is .3 amperes. (three tenths of one > ampere) No big wonder why small wire (with BIG insulation) will produce > the power. > > This is the same law that allows the power company to use small wire to > serve hundreds of homes with electricity. There is thousands of volts > on the PRIMARY of the transformer on the pole that serves your house. > The secondary has a few hundred volts at a few hundred amps. > > Those big battery charger / starters that have the ability to start a > vehicle with a dead battery.... they put out many many amps, 50 - 100 > amps of current, but are run from a common extension cord.... I think > now you see the point... > > Kevin Custer >
