Nichrome res reading?

I cut a smal piece of nichrome to test it's length vs resistance and I'm looking for some clarification. This might sound odd to some of you, but I would like clarification please.

example: I test a 10k resistor on the 20k setting and I get 10, as I should. Which means that the k adds the 3 zeros, at 2k it would measure 100 (plus the 3 zeros) (it doesn't, but theoretically it should).
With this in mind to actually get the 6-8 ohms for the nichrome wire it would have to read 0.06 on the 200 setting right? That just sounds ridiculous to me.

I tried it with the piece I cut at about 1.5" and it gave me a reading of about 1.2 on the 200 setting, if I am reading it right, doesn't that actually mean that it's 120 ohms? If this is the case, then doesn't that mean that it should be 600-800ohms length used on the extruder head? This would make it work for the 6-8 inch length that everyone talks about.
If I am just being a dummy and reading my voltmeter wrong, please just let me know.


One other problem I have is how to solder to it. Any ideas?

Thanks

Dylan

Edited 1 time(s). Last edit at 01/28/2008 11:11PM by Dylan.

My multimeter's display has 3.5 digits - that is, 3 full digits and a "1". Therefore, it can only show me the 4 most significant digits of any reading. So, when set to 2000v, if I measure 1v, it'll (probably say) 1, whereas on the 2v range it'll say 1.013 or something. Clearly, using the lower range gives me more precision.

However, every digit has its own decimal point, and that point will always directly translate - on my 200r range, a reading of 10.0 means literally 10 ohms, and on my 20k range, a reading of 10.00 means literally 10k.

If your meter reads 1.2 on the 200r range, you're seeing 1.2 ohms.

Ok, that makes it more clear. So apparently the "k" is the only thing that translates to change the decimal place. I suppose that means that the piece I cut was then in fact a 1.2ohm length.

Any idea how to solder that to my wires, it's quite a pain?

thanks

Dylan

Don't bother trying to solder. The wire will get hotter than solder's melting temperature and solder doesn't stick to nichrome very well, so soldering is both futile and dangerous.

Instead, crimp them. Some copper or brass thin walled tubing should do nicely if you don't have anything more suitable lying around. I use my wirecutters to crimp stuff like that.

Remember that the wires you attach to it must have insulation that can withstand 250 celsius or more, so you may need to strip back quite a bit and put on some fibreglass sleeving ("spaghetti"), maybe 6 inches or so.

Ok, I'll try something like that.
thanks

Dylan

one thing i like to do is use screw terminals. you can either get ones with a screw opening on both sizes and then just screw both wires together, or you can use the ones that are meant to solder to a board, and just solder your normal wires to the solder points and then screw clamp the nichrome in.

Thanks, that's another good idea. I'll probably try the clamping thing first though. I always have some extra metal around.

Dylan