Inexpensive replacement pot for external use with a servo?

Feb 11, 2007 2 Replies

Can anybody suggest a small inexpensive pot for external use with a standard hobby servo? I'd like to use an external pot placed at a joint to control a remote servo. It appears that that the servo pots are of the 5k type, but the inexpensive 5k pots I see in Jameco and such seem to operate over a range of ~300 deg instead of a smaller range normal for the usual joint movement. To get a smaller operating range, would the lower range of a 10k pot work to cover a ~150 deg range? Any info would be much appreciated! Thanks!


The pots in servos have a similar range (about 300 degrees), even if the servo itself doesn't physically, so I think you'll have basically the same functionality.

One difference you might encounter is that pots can have either a linear or log taper. I'd bet most servos have a linear taper; the log taper pots are generally for audio applications. In any case, it's something to be aware of if you're purchasing a pot. If you can, take the servo apart and measure the pot -- you'll have to take that one out anyway to replace it with an external one. If it's linear taper the resistance will change linearly as you rotate it. You want to make sure you get a linear pot to match.

-- Gordon

Thanks for the quick reply. I've got an old servo that has gotten jittery, so I can check the pot when I take it apart and try to clean its pot with some contact cleaner. All part of an idea to make an inexpensive servo controlled/operated arm out of Walmart yard sticks. ;)

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