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Can any one tell me how to make this inductor? Answered

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Can any one tell me how to make a 0.35mH inductor what will be the turns and what will be the coil dia.?
the circuit is shown below.

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rickharrisBest Answer (author)2013-04-10

For once this is something you can ex[eriment with.

Get a ferrite core (possibly from an old AM radio) It's a long black rod.

If you get it from an old radio it will have a coil on it you can try that.

Wind on around 50 - 100 turns of thin enamelled covered wire in a single layer.

Wind on 2 to 10 turns for the second coil and connect the end of one to the other. Giving you 3 connections to use.

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steveastrouk (author)2013-04-09
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Re-design (author)steveastrouk2013-04-09

And I meant to say that the coil provides Antenna tuning. The radio will work better when the tap is in the right place or not at all unless the station is strong if the tap is in the wrong place.

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steveastrouk (author)Re-design2013-04-09

Meh, its only a crystal set derivative ;-)

Heartily recommend the book "Voice of the Crystal" about making a crystal set, completely from scratch.

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Kiteman (author)2013-04-09

Can't you buy one? For example;

http://www.amazon.com/Jantzen-0-35mH-AWG-Core-Inductor/dp/B0002M72N4

http://www.madisoundspeakerstore.com/air-core-19-awg/madisound-0.35-mh-19-awg-air-core-inductor/

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Re-design (author)Kiteman2013-04-09

Neither one of them will work here because the inductor needs a tap somewhere. The tap will provide the antenna tuning function so it probably should be adjustable.

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Re-design (author)2013-04-09

The first coil in this link would probably work.  Either use a sliding contact or find where it works best and solder or clip the tap there.

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steveastrouk (author)2013-04-09

+1 Missed that.

YEp, you have to wind your own, and tap the centre of the inductor.

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steveastrouk (author)2013-04-09

There are LOADS of online calculators for air core inductances, or you can, as Kiteman says, buy it.

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