September 2011
How do I increase the resolution of a variable resistor (pot)? I have to move the knob so slightly that I can't fine-tune or properly adjust the resistance in the circuit. Any type of solution would be appreciated.
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A schematic along with the pot resistance would have been helpful, but here are some things to try.
The problem is too much voltage across the pot. The large voltage change at the wiper as you turn the shaft a few degrees makes it hard to fine-tune. If the pot is not connected to a low impedance source such as a power supply or battery, put a resistor across the end terminals to reduce the voltage across it. Try a resistor about 20% of the pot resistance.
This will help you fine-tune, but now the voltage range at the wiper may not be right for your circuit. In that case, or if the pot is fed from a low impedance source, connect resistors from each end terminal to the wiper instead of putting a resistor across it. Keep the sum of the resistors about 20% of the pot resistance, and try various combinations of resistor values until you get the required range.
