signal interfacing
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Hey All:
I have a circuit that uses a 555 timer with a 5k pot to control it. I need
to interface a 2.5 - 5 volt dc voltage to change the resistance of the main
5K pot. (Like a voltage controlled pot in series with the 5k) The goal is to
use the varying voltage to control the 555, but also to keep the 5K pot as
an overall range adjust. I know this is off topic, but I do plan on
converting to a Stamp circuit eventually. Any help is much appreciated!!
-Steve Chlupsa
I have a circuit that uses a 555 timer with a 5k pot to control it. I need
to interface a 2.5 - 5 volt dc voltage to change the resistance of the main
5K pot. (Like a voltage controlled pot in series with the 5k) The goal is to
use the varying voltage to control the 555, but also to keep the 5K pot as
an overall range adjust. I know this is off topic, but I do plan on
converting to a Stamp circuit eventually. Any help is much appreciated!!
-Steve Chlupsa
Comments
A Jfet or small mosfet in series or parallel with the pot. Scale the 2.5 to
5 volt signal to modulate the fet to desired resistance.
Ray McArthur
> I have a circuit that uses a 555 timer with a 5k pot to control it. I need
> to interface a 2.5 - 5 volt dc voltage to change the resistance of the
main
> 5K pot. (Like a voltage controlled pot in series with the 5k) The goal is
to
> use the varying voltage to control the 555, but also to keep the 5K pot as
> an overall range adjust. I know this is off topic, but I do plan on
> converting to a Stamp circuit eventually. Any help is much appreciated!!
You might be able to modulate the 555 pin 5 reference voltage instead. A
series resistor may be the only required interface...
>I have a circuit that uses a 555 timer with a 5k pot to control it. I need
>to interface a 2.5 - 5 volt dc voltage to change the resistance of the main
>5K pot. (Like a voltage controlled pot in series with the 5k) The goal is to
>use the varying voltage to control the 555, but also to keep the 5K pot as
>an overall range adjust. I know this is off topic, but I do plan on
>converting to a Stamp circuit eventually. Any help is much appreciated!!
Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
Manufacturer of the famous BOB-II Serial Video Text Display Module!
Thanks!
I'll try that.
-Steve
Original Message
From: Mike Hardwick <decade@w...>
To: <basicstamps@egroups.com>
Sent: Monday, July 03, 2000 2:42 PM
Subject: Re: [noparse][[/noparse]basicstamps] signal interfacing
> Steve,
>
> You might be able to modulate the 555 pin 5 reference voltage instead. A
> series resistor may be the only required interface...
>
> >I have a circuit that uses a 555 timer with a 5k pot to control it. I
need
> >to interface a 2.5 - 5 volt dc voltage to change the resistance of the
main
> >5K pot. (Like a voltage controlled pot in series with the 5k) The goal is
to
> >use the varying voltage to control the 555, but also to keep the 5K pot
as
> >an overall range adjust. I know this is off topic, but I do plan on
> >converting to a Stamp circuit eventually. Any help is much appreciated!!
>
> Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
> Manufacturer of the famous BOB-II Serial Video Text Display Module!
>
>
>
>
>
Thanks!
I'll try that.
-Steve
Original Message
From: rjmca <rjmca@w...>
To: <basicstamps@egroups.com>
Sent: Monday, July 03, 2000 12:09 PM
Subject: Re: [noparse][[/noparse]basicstamps] signal interfacing
> An offhand idea:
>
> A Jfet or small mosfet in series or parallel with the pot. Scale the 2.5
to
> 5 volt signal to modulate the fet to desired resistance.
>
> Ray McArthur
>
> > I have a circuit that uses a 555 timer with a 5k pot to control it. I
need
> > to interface a 2.5 - 5 volt dc voltage to change the resistance of the
> main
> > 5K pot. (Like a voltage controlled pot in series with the 5k) The goal
is
> to
> > use the varying voltage to control the 555, but also to keep the 5K pot
as
> > an overall range adjust. I know this is off topic, but I do plan on
> > converting to a Stamp circuit eventually. Any help is much appreciated!!
>
>
>
>
>
>
>