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
