Cgs synth

Range will affect the offset with the circuit as shown.
If you want the offset to be totally independent of range, reverse the power
connections to the offset pot, and connect the wiper via a 47k to pin 6 of
the op-amp instead of pin 2. Pin numbers given as per my diagram: you'll
need to substitute your own pin numbers. If the resultant offset range is
too large, put a trimpot in series with the 47k resistor.

Ken

>Hi all,
>I am working on the joystick circuit from here:
>http://www.cgs.synth.net/modules/joystick.html
>and I have a few questions about it... it doesn't seem to be behaving
>as expected.
>
>I am using a TL074 as the op amp.
>
>The range control at minimum causes the joystick's travel to change
>the voltage output very little as expected. However, when I try to
>add offset to the output in this state, it adds almost nothing...
>like 0.2 volts or something. Offset seems to work OK when the range
>is high. I was hoping that I could set it up so that the travel of
>the joystick could make the output range from 0V-5V if I wanted or
>from 4.5V - 5V if I wanted. Is this a possibility with the circuit
>as it is designed?
>
>Also, I am having trouble setting the values (with the range pot at
>maximum). I have tried it with the bottom of the joystick hooked to
>the neg. rail as suggested, and also with it hooked to ground but it
>is not ever giving me a range of 0-5V no matter how I set the values.
>
>Any help appreciated.
>
>Rafael
>
>
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>
>Yahoo! Groups Links
>
>
>
>

_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>
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