0.1 ohm Resistors from Scratch Again

\"Watt

limited

max).

concerned

put a

when

wire in

heated

Sounds to me, Don, a lot like the tungsten wire in a light bulb. ;-)

part:

long

in

I've since gone to the larger 36 AWG, which is a bit under 3 inches for a tenth of an ohm. So no problem.

\"Watt

PS

the

handle

which

that

And, IIRC, it's also a lot more difficult to solder.

\"Watt

soldering

of

turns

but

When I

the

right

I think what's happening is when I pinch it with my fingers, I'm cooling it, not warming it.

about

zero

Recently I had to do some work in the physics lab at our other campus (they have some HP 6205 power supplies for doing some experiements). They have several of these "slidewire" resistance wire gizmos. The description says it uses nickel-chromium, I presume is the same thing as nichrome.

When you think about it, this is how Sir Thomas and Luigi and the others started out, except they used batteries. Some interesting experiments here.

the

thereabouts.

"experiment"

I'm making my own 0.1 ohm resistors. I can't buy (locally, anyway) a small 0.1 ohm resistor, and I don't need even a tenth of a watt dissipation when I use it for current sensing. And I can't buy special wire other than copper in small quantities locally. I could buy a wirewound resistor and break off the ceramic and cement hopefully without damaging the wire, and then use the wire to wind some other resistors. But I'm doing just fine with 2.9" (73.4mm) of 36 AWG copper wire wound on a 1/4W resistor. It's reasonably accurate, maybe within

but

total

"experiment"

Thanks, J.F. You're beginning to sound like Toak/Nunya whatever. I'm just trying to share my experiences with others. If you don't have anything constructive to say, then I invite you to make no comments. But then we all know that you wouldn't take my invitation seriously. Have a nice day.

about

Of courese not, silly! Everyone knows it was made from the throne of the great Roman ewmperor Constantine (until they ran out, and had to use his chamberpots)! ;-)

about

Anyone (in the U.S. at least) watch Guns, Germs and Steel on PBS the other night?

They showed how a couple hundred conquistadors decimated tens of thousands of Aztecs with this silly blunderbuss or trabuco, which could barely hit the side of a barn. And their horses, of courses, had a lot to do with it. Interesting.

selection.