Turn a log pot into a (kind of) linear pot

[osterchrisi]

Hey there!

I made a terrible mistake in a circuit that I have to fix now: I ordered 250 wrong potentiometers (logarithmic scale) but they should be linear. Ordering new ones is not an option as this would take 8 weeks to wait for but we start production next week.

Is there ANY way of hacking a logarithmic pot into a linear-like one? The resistance value is 100K but I also wouldn't mind loosing part of this range, to like 50K or whatever.

Any clue anyone?

PS: Cross-posted this also on the electronics point forum for desperateness' sake...

 

[osterchrisi]

Mhm, thought I attach some more info: The log pot is actually responsible for setting the speed of a 555 timer (you know, between Trigger and Discharge). So maybe there are more possibilities of changing the logarithmic behaviour of the setup?

 

[mickeymoose]

Look at pix 3a and 3b, making a lin pot into "log". This should help you linearize your pot. E

 

[osterchrisi]

Thanks, mickymoose!, I know that trick already, works really nice 🙂 But I want to perform the opposite: Converting a log pot into a lin pot...

 

[Frank Berry]

You can convert log to lin if you follow the "B" schematic.