Threaded Mode | Linear Mode

Dave Frederickson · (This post was last modified: 02-17-2021 11:02 PM by Dave Frederickson.)

(02-17-2021 06:46 AM)James Linder Wrote: I ordered the PCB mount potentiometers. I see they have 3 connectors.
Is the third connector just for a ground wire? I assume if yes, is this 3rd
connector the middle prong? Do I Just connect the middle prong to the black
wire going to the battery? Are the other 2 connectors bidirectional (does not matter
Which one is connected to R8 and which end is connected to the PCB connector?

Which end of the pot you connect depends on whether you want the print to get darker when you turn the pot CW or CCW. Also, it's common to see one end of the pot connected to the wiper. This ensures that if the wiper experiences contact bounce that the max resistance will be that of the pot.* If it were not connected the pot would show an open, for a very short period of time, but depending on what the pot adjusts the result could be bad.

Dave

*EDIT: On second thought, it's not contact bounce as the wiper has multiple contacts. The issue is corrosion which can cause momentary open circuit conditions. This is exhibited commonly as a scratchy volume control or brightness control. Consequently the makers of DeoxIT have something called Fader Cleaner that worked wonders on my 82912A's brightness and contrast controls.