Construccion De Resistencias De Bajo Valor

How to Make Copper Wire Resistors
DIY low value resistors.

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If you need a low value resistor quickly, or happen to need one with a
temperature coefficient of resistance of +0.393%/°C itseasy enough to make.

The first time I had to make a resistor, I was in an apartment in Bangkok, well more than an hour's ride and half an hour's walk to the nearest electronics component outlet.Basically, it would have been a half day trip to go out and look for a 0.1 ohm resistor that I needed for the EDFET amplifier breadboard. I needed a ballast resistor to go between two emitterfollowers. Something small fraction of an ohm would do, so I reached for a spool of magnet wire. 

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Above: The first time I needed to make a resistor.
The red axial leaded component is a 0.1 ohmcopper wire
resistor.

I like to use resistors as the winding form for these hand-made resistors. If you just take a resistor and wind a bunch of wire on it, you have made something with resistance,but it will also be a pretty good inductor. Using the winding method illustrated below will result in a low inductance for the resistor. Making the wire into a twisted pair assures better couplingbetween the wires, thus assuring lower overall inductance.

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Above: Low inductance winding method, illustrated and placed in the Public Domain by the Zureks.

The method applied in the examplebelow can be extended to a wide range of resistance values. While you can get a given resistance with anywhere between a short thin wire and a long heavy wire, two things should be kept in mind: Longheavy wires will have a longer time constant, which may be a significant factor, depending up on the application, and long thin wires have lower fusing currents. Please check the wire tables for thewire you intend to use for fusing current.

Below you can see how I made my low inductance, low power 0.1 ohm shunt current sensing shunt for a wattmeter that required an approximately 3300 ppm...