# The perfect resistor

#### Solardon

Joined Oct 5, 2006
5
Hi, I am new here. I am an electronics hobbyist. I love to tinker with things to see how they work. Been like this ever since I was a kid.

I would like to start out here with a general question that is pretty interesting - I think.

There are standards in science and technology that are used as measuring standards. There is a mass that is exactly one gram. A length that is exactly one meter. An atomic clock that keeps perfect time. etc, etc. What about the lowly resistor?

Is there some resistor somewhere that is exactly one ohm? One particular one that is used as a standard? Lets say I go and measure it's resistance with a "perfect ohmmeter" today and get exactly one ohm. Then I go back ten years later and measure it again with the same "perfect ohmmeter" and get exactly one ohm. And this resistor is so perfect that in one thousand years from now it is still exactly one ohm?

This may sound like a peculiar question. Or just simply food for thought. But it is pretty interesting to know if such a resistor existed.

Anyway; Thank you. Hope to meet some of you in the forum.

Don

#### thingmaker3

Joined May 16, 2005
5,083
No. And yes.

From the official meter and the official kilogram we may calculate an official joule and an official newton. One joule per coulomb is one volt. The definition of ampere is "0.0000002 newton of force per meter of length between two infinitely long conductors of negligable diameter separated by one meter in a hard vacuum." Yeah, its a cumbersome definition. Anyway - an ohm is defined as one volt per ampere.

#### pebe

Joined Oct 11, 2004
626
I remember the definition of an ohm given in my schoolboy days was:

'The resistance between the ends of a column of mercury 106.3mm high and 1sq.mm. in cross section, at the temperature of melting ice',