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Old 12-03-2016, 08:52 PM
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wa2ise wa2ise is offline
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Quote:
Originally Posted by old_tv_nut View Post
If the nominal voltage is close to zero, put the trimpot between two larger value resistors to limit the range. ...
I also used a better quality trimpot, which was also ten turns as well. And I added a pair of diode strapped transistors (base tied to collector for the anode if NPN, the emitter is the cathode) as 0.6V zener style voltage shunt regulators to both ends of the trimpot. Diagram shows diodes there. One on each end, to give me 0.6V and -0.6V. This to keep the trimpot adjustment voltage stable over varying powerline voltages.

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Last edited by wa2ise; 12-03-2016 at 10:25 PM.
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