inductance of a resistor

Thread Starter

jrdoner

Joined Feb 21, 2012
14
Hi,

This will be my first post, so if I inadvertently violate a house rule, let me know.

My question is this. I need some very low-value resistors (well under 1 Ω), and I am going to make them by using a known length of nichrome wire. That would give me a resistor that is also an inductor. However, it occurred to me that if I wound half the wire clockwise, and then reversed and went counterclockwise, I should have created two possibly cancelling magnetic fields. After all, no magnetic field, no inductance, eh?

So I tried this, using a magnetic compass as a detector, and the compass needle swung 7 degrees with the coil would only clockwise, but only about 1 degree for the coil with the reverse in the middle (all other conditions being equal).

So, was I fooled, or does this idea make sense?

Thanks in advance for any responses.

jrdoner
 

crutschow

Joined Mar 14, 2008
34,201
An easy way to wind a bifilar resistor is to fold the wire in half and then wind the two wires close together on a core starting from the fold. That way you always have adjacent wires with opposite currents which gives maximum inductance cancellation.
 
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