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Resistors as Chokes

Jun 9th 2015, 18:01

WD6EJN

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
When I was a kid I had a project that used resistors as self wound chokes,
I know a bout the power of resistor but does the value of the resistor effect the permiabillity of the choke?
Jun 9th 2015, 18:20

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

The resistive materials that I can think of, namely carbon and nichrome, are non-magnetic, but who knows what you might find at the hamfest.

I would measure it if I had any doubts about it. Preferably at the frequency of interest--an antenna analyzer is a readily available tool for doing this.

Zack Lau W1VT
ARRL Senior Lab Engineer
Jun 9th 2015, 21:23

WD6EJN

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Quote by W1VT

The resistive materials that I can think of, namely carbon and nichrome, are non-magnetic, but who knows what you might find at the hamfest.

I would measure it if I had any doubts about it. Preferably at the frequency of interest--an antenna analyzer is a readily available tool for doing this.

Zack Lau W1VT
ARRL Senior Lab Engineer

I'm trying to make a low pass filter for a very tinny high impedance high gain microphone preamp (stereo hearing aid Ramsey Electronics) that I am specially building for a senior lady here and she also says it picks up too much back round noise rather then who she is speaking with, here's another problem! how do I add a third microphone to make it noise cancelling,,,L-R ? using home made low pass filter?
I wound these coils on 100-400k 1/4 watt resistors
each coil is around 1k of resistance and a bout 1/4 of an each round.
to make three series coils or six for both channels.
There seems to be a very small attenuation of the higher but not much.
I think I may have created a business here as another senior may want one!
The only way to check this is to substitute a coil for an existing one in an existing circuit and listen on a sw receiver as my mfj analyzer bit the dust a long time ago I added some iron by making e-cores out of used magnetic business cards, so it seems to work in the audio range, I just use a paper circle cutter.
Oh! I now stick all my resistor projects to rare earth magnets instead of placing in a cheap box or pill bottle....I hope this doesn't do any thing or damage the resistor.
Although quite large, I'm now winding coils on surplus 1 watt resistors, this seems to have knocked the frequency down, now I have a boom box amp.

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