Re: a variable frequency resistor

To: tesla-at-pupman-dot-com
Subject: Re: a variable frequency resistor
From: Jim Monte <JDM95003-at-UCONNVM.UCONN.EDU> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sat, 08 May 1999 14:10:06 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme


>Date: Fri, 07 May 1999 11:29:56 -0600
>To: tesla-at-pupman-dot-com
>Subject: a frequency-variable resistor   Re: request for braid data
>  (was Another grounding question)
>
>Original Poster: "Bill Noble" <william_b_noble-at-email.msn-dot-com>
>
>aaah, wouldn't a frequency variable resistor be an inductor?  (if you wanted
>more ohms with increasing freq) Or perhaps a capacitor??? (for the opposite
>effect)
<snip>

  Not really.  Both inductors and capacitors only store energy and give
  it back later.  The "give it back later" can be a problem since it may
  result in something just about as bad as what you were trying to
  filter out.  Terry has a nice oscillogram on his web site somewhere
  that shows this happening in a neon transformer filter.  Resistors
  will dissipate energy as heat, and consequently it cannot come back
  again to haunt you.  So resistors are a bit more fail-safe if you are
  not sure exactly what you will be getting for an input.  Of course you
  pay for this in terms of greater losses.

  Jim Monte