In a transformers output, is it the current that is fixed or the voltage?(adsbygoogle = window.adsbygoogle || []).push({});

I have been trying to resisitively heat some tungsten foil and I am stuck at trying to find out the amount of current I need in my transformers output. The problem I am facing is that I know that the tungsten resistivity will increase as it heats up, but I need to make sure my tungsten reaches the temperature of 1035 Celcius that I need at it. Specificly, I want to know if my power dessipated to tungsten foil, will Increase or decrease, as the resistance increases due to heating.

The reason is that I am confused between the two formula's: P=I^2R, P=V^2/R.

In P=I^2R, resistance increases, power increases(considering transformer gives constant ampere output)

In P=V^2/R, resistance increases, power decreases(considering transformer gives constant voltage output).

My question to you is:

1)Which is fixed in a high current transformer,(Current or Voltage)?

2)Is it possible that fall in current will be negated by increase in Resistance, so that power dessipated remains constant?

Umar Awan

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# Is it current or voltage that is fixed in transformer output

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