I've got other idea. I'll get meters of high gauge wires and measure
3 ohms and use it as resistor. How do I calculate how much will it
heat up?
That depends on a lot of factors, for example when you wind it like a coil
it will heat up a lot more then when you leave it laying about.
I've got Resnick and Holliday 800 page book on
Electromagnetisms and still slowly going thru it but need the
information asap. Thanks.
Try it!
There is special resistance wire, that you can use to make your own
resistance. Google:
http://www.surplussales.com/Wire-Cable/Resistance.html
Then you can use shorter length.
Say. Is there a difference in performance if I have say a 20 meter
thin cooper wire measuring 3 ohms versus a thick 5 meter cooper
wire measuring 3 ohms also?
Well, since you want to measure magnetic fields, I would use a light bulb,
because that wire (especially when the 20 meter is wound) will be a coil
of its own, with its own magnetic field, interfering with your setup!
I presume you meant 20 meter thick versus 5 meter thin.
Thanks. It explains why I fried my power transistors 2 times
already. Well if I never go below 60 Hz but go higher to 10Khz.
Would it also fry the circuit?? I notice a high pitch sound in
the circuit when the frequency is increased linearly from 60 Hz,
to 10 kHz.
At higher [switching] frequencies the switch time of the transistors
becomes important (they will dissipate heat while not 100% on or off),
and also the losses in the core of the transform will increase.
Then there is 'skin effect' in the wire (electricity only flows in outside).
For this reason above say 3 kHz you will often see ferroxcube (ferrite)
cores.
And possibly litze wire (wire made up of many strands).