Electronic – how to make a W potentiometer from a log or linear pot

potentiometer

My circuit needs a s-curve type of pot, that is a W pot but i cant find it in a store.

How can i make a W pot Either using a log or a linear pot?

w pot graph
graph

W pot=G pot
Does anyone have a G pot graph?

Best Answer

What are you going to do with the result? Things are mostly controlled digitally nowadays, which is why there is little point to non-linear pots anymore. Set up the pot to drive the A/D input of a microcontroller, then perform whatever non-linearities you want on the resulting linear reading.

Even in the unusual case where you really do want a non-linear analog voltage from the user setting, you can still use a cheap micro (under $.50) to read the pot, perform the non-linear function, produce PWM from than, then a R-C filter to make the average voltage level. The linear pot plus micro is often cheaper than the fancy low-volume non-linear pot.