[sdiy] Carbon composition... vs carbon film resistors..

[Barry Klein]

Check this thread: http://www.geotech1.com/forums/showthread.php?20169-Need-advice-on-Minelab-11-quot-coil-repair-and-design
The resistor I am talking about is shown in comparison to the original in-circuit one.
I suspect metal film.  No capacitance involved unless it's in the meter :-)
It is interesting to learn as - in the first place I did not expect to see a damping resistor on an RX coil - then it skews the inductance measurement of the coil and thus if you try and copy an existing design you need to know whether there is a resistor there or not.
Too many hobbies already BTW.  I need to remain clueless with the ones I have.

Barry


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Paul Schreiber
Sent: Monday, February 11, 2013 10:37 PM
To: 'synth-diy'
Subject: Re: [sdiy] Carbon composition... vs carbon film resistors..

> LC102 for inductance and got 233uH

According to the "math", that inductance would have to be in series or parallel with *at least* 0.28uf just to have an effect at 20KHz.

If your pc boards have 0.28uf of stay capacitance, get another hobby :)

Paul S.

 

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