Homebrew Vactrols

[Martin Czech]

CdS has two humps, one in red , one in green.

So green or red leds work. Red is more efficient.

m.c.

:::Date: Mon, 17 Apr 2000 09:11:15 -0700
:::From: Jules Ryckebusch <ryckebu at ersg.san.mrms.navy.mil>
:::To: René Schmitz <uzs159 at uni-bonn.de>
:::CC: synth-diy at node12b53.a2000.nl
:::Subject: Re: Homebrew Vactrols
:::Content-Transfer-Encoding: quoted-printable
:::
:::I have used Green LED's with good results. Built a Phase shifter that way.
:::Thge key is to have a low on resistance woth the LDR. Use a ohm meter and be
:::sure to roughly match them.
:::
:::Jules
:::
:::René Schmitz wrote:
:::
:::> Hi all,
:::>
:::> inspired from Grants "Assimilator" filter, and after realizing that I have
:::> never worked much with LDRs/Vactrols, I have started to experiment with
:::> LDRs driven from LEDs.
:::>
:::> What is the best LED color for driving a CdS LDR? So far I only tried
:::> orange ones.
:::> Or to put it the other way, at what wavelenghts has the CdS the highest
:::> sensitivity?
:::>
:::> Are there any good reasons to use an off-the-shelf vactrol instead of a
:::> roll-your-own?
:::>
:::> Bye,
:::>  René
:::>
:::> transconductance | uzs159 at uni-bonn.de
:::> isfutilepreparet | http://www.uni-bonn.de/~uzs159
:::> obeassimilated.. | http://members.xoom.com/Rene_Schmitz