voltage controlled resistors

[Uros Milicevic]

----- Original Message -----
From: Magnus Danielson <cfmd at swipnet.se>
To: <t02e at hotmail.com>
Cc: <synth-diy at mailhost.bpa.nl>
Sent: Monday, February 14, 2000 8:59 PM
Subject: Re: voltage controlled resistors


> From: "walter carpenter" <t02e at hotmail.com>
> Subject: voltage controlled resistors
> Date: Sun, 13 Feb 2000 20:19:13 PST
>
> > This might be a stupid idea, but has anyone ever built a simple "voltage
> > controlled resistor" that, with a switch, could override a
potentiometer? is
> > this possible? it would be nice to have lfo's controlling as many things
as
> > possible :)
>
> Hm. This really sounds like something you would build with OTAs. One or
> possibly two OTAs in a gyrator setting should be an interesting thing. For
> most settings will a single OTA be suiteable, but if you need both ends of
the
> resistor to "float" and push/pull current I think a little more advanced
tricks
> have to be used. Hmm...
>
> Cheers,
> Magnus
Or you can use discrete OTAs or you can use fet transistor . It depends for
what you need it .
I think ( I'm not an expert so I may be wrong ) it is best to designe
circuit with VC in mind and not to apply VC to nonVC circuit ( I'have
feeling that you want to change pot with VCresistance
Usualy circuit can be much simpler if you use Vc from the start ( this is
IMHO ) . If you need to change existing circuit and you need it badly maybe
someone from the list ( I'm not pretending of being capable of doing that )
could do it for you .OTOH I realy should not speak
in other people name .
When we are talkin about resistors and pots could someone give me some info
( or point me out where to get info ) on motion tracking device ( what a
terrible description ) from mouse
Im refering to two pot look-a-likes that tracks motion of rubber ball . Im
shure it is light based
and that it uses descrete logic but what is sensor for light ( it certanly
dont need  LDR ) ? Voltages , suply voltages , circuit layout ?
Thanks in advance

Uros