- #1

- 109

- 0

**What is the difference between 100V 30A and 300A 10V ???**

Hello, I am very new at this so please guide me on the following issue;

Lets say I have an electrical resistor with a resistivity of 1.5*10^-5 ohm m (graphite)

and lets say the total resistance of this particular graphite heating element is 0.15ohm and I need it to heat up to 2000 kelvin.

Considering the power required to radiate 2000 K is 3000 watt, how should I determine the required voltage and current...???? I do know that graphite heating elements are only used with dc step down transformers, but how low should the voltage go?!

if I hook this up to a 100V 30Amp or 10V 300A transformers the result is 3000 Watt in either case, so what is the difference?! I think I am missing something very fundamental here... PLEASE help...

The way I got 3000 watt as the required power is from the black-body radiation's formula :

Power=(surface area of blackbody)*(boltzman constant)*emissivity*(Temperature)^4

is this a good method for a rough approximation (+/- 500 Kelvin) ?

or correct at all?

Thanks in advance.