[NTLK] OT - Wire Gauge Recommendation for eProbe/eMate Experiment?

[Andrei Chichak]

The answer is; it depends.

First, you can get 2.2K resistors at your local Radio Shack, 5 for $1.49. Unless you are doing something esoteric, any type will do. If you have a buddy that does electronics for fun, he could just give you one. 2.2K is a standard value, commodity, boring, resistor.

Thin wire has more resistance, thick wire starts getting cumbersome. Thin wire has less ability to carry current before, due to its higher resistance, heats up and melts down. Thicker wire can do some odd stuff when run at high frequencies, but if you are measuring stuff greater than a megahertz you will have to understand the system very well to get a good measurement. If you are going long distances, like 10s of meters, a thicker wire will be necessary since wire has resistance that goes in ohms per foot/meter. Short distance, thinner wire. Long distance, thicker wire.

Insulation gives the ability to form a high resistance barrier. Voltage will find the least resistive path. Therefore, insulation good. Insulation useless at really high voltage, see lightning.

So, what does the answer depend on? Anybody? Anybody? Buhler? Correct, it depends on what you are measuring. 

If you are measuring lightning, the 2.2K resistor will explode unless you get one that is rated for several hundred million volts and tens of thousand amps and thus terra watts (the Benjamin Franklin kite thing is completely bogus BTW).

If your voltage is small (5V) and the current is small (milliamps) then you can get away with small, thin insulation wire.

40 gauge wire-wrap wire is good for about 90mA.
30 gauge about 860mA.
24 gauge about 3.5 amps
20 gauge about 11 amps
10 gauge about 55 amps
00 guage welding cable about 280 amps.

Andrei


On 2013-February-11, at 10:43 AM, SteveCraft wrote:

> 
> 
> I am attempting to do an experiment with the eProbe software and eMate, and
> it calls for using a "2.2k-ohm resistor". I believe I found this item:
> 
> 
> 
> http://www.amazon.com/gp/product/B0002KR6FK/ref=ox_sc_act_title_1?ie=UTF8
> <http://www.amazon.com/gp/product/B0002KR6FK/ref=ox_sc_act_title_1?ie=UTF8&p
> sc=1&smid=A2T9G15QSM4M3M> &psc=1&smid=A2T9G15QSM4M3M
> 
> 
> 
> But I am not sure what gauge of wire I would need for it. Thin as possible,
> and insulated. Can anyone make a recommendation?
> 
> 
> 
> 
> 
> Thanks.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> ==================================================================== 
> The NewtonTalk Mailing List - http://newtontalk.net/
> The Official Newton FAQ     - http://splorp.com/newton/faq/
> The Newton Glossary         - http://splorp.com/newton/glossary/
> WikiWikiNewt                - http://tools.unna.org/wikiwikinewt/
> ====================================================================