There are a zillion resistor value pairs that you could use. The important
factor to get a specific voltage is the ratio between the two resistors.
Blah blah insert a bunch of irrelevant theory here....
Bottom line:
Connect a 10K resistor to ground, and a 5.1K resistor to +15V of your MOTM
supply. Connect the free ends of the 2 resistors together, you'll get about
10V there. That's without trying to drive much of a load. To make the
circuit stable, connect the resistor junction to a voltage follower, which
is just any old opamp's positive input, with the negative input connected
directly to the output. Then the output of the opamp connects to one
joystick pot leg, the other pot leg goes to ground, and the pot wiper is the
joystick output.
Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@... > -----Original Message-----
> From: thomas white [mailto:djthomaswhite@...]
> Sent: Wednesday, April 12, 2000 1:50 PM
> To: motm@egroups.com
> Subject: Re: [motm] Power Supply and Joystick advice
>
>
> Thanks JB,
>
> I just want to get a rounded opinion on the max voltage I should
> use. I am
> pretty new to figuring out resistance since I come from a purely
> "A into B"
> kit background (Duh). So what values in the voltage divider would
> I need to
> scale down to 10v? Thanks,
>
> Thomas White
>
> >From: jwbarlow@...
> >Reply-To: motm@egroups.com
> >To: motm@egroups.com
> >Subject: Re: [motm] Power Supply and Joystick advice
> >Date: Wed, 12 Apr 2000 14:33:02 EDT
> >
> >
> >In a message dated 4/12/2000 9:44:23 AM,
> djthomaswhite@... writes:
> >
> > >On the joystick level, I am looking for the best way to drop
> the +15/-15v
> > >volts from the 900 PSU to +10/-10v or +5/-5v for joystick use. Which
> >voltage
> > >do you guys recommend?
> >
> >Doesn't the Klein schematic show something about a lower voltage
> (like 10V
> >maybe)? I say split the difference with a voltage divider (didn't I put
> >something about this in there too)? Take one 100K resistor and
> put one side
> >at 15V and on the other side place 1) a second 100K resistor, and 2) an
> >OUTPUT. Connect the other side of the second 100K resistor to ground. The
> >OUTPUT should be about 7.5V. I know I put some stuff about scaling and
> >offsets in there, take a look at that too.
> >
> >I hope someone smarter than me will chime in and correct any
> errors I may
> >be
> >spreading -- but it should be OK for a FracRack!
> >JB
>
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