I cant figure out which pin is the number 1 on the potentiometer and variable resistors within this schematic. I would guess that the circle with a slash through it is pin one but I'm not sure. Any help would be appreciated. Thanks in advance!!! Schematic link below.


  • 1
    \$\begingroup\$ No. The circle with a slash through it means it is a PC mounted trim pot. You use a tiny flat tip screw driver to adjust it. End points, if marked at all, usually have a CW or CCW marking for 'clockwise' or 'counter-clockwise' end. These are often crucial fine-trim adjustments and to tamper with them is asking for trouble. \$\endgroup\$
    – user105652
    Commented Jan 29, 2018 at 3:12
  • \$\begingroup\$ I don't have this unit but I would like one. Im making a PCB for myself and a friend but cant figure out the pins on the schematic. I suppose i could just switch the wires as im not board mounting the pots. Thanks for your help though, I always wondered what the circle with a slash through it meant and now I know. \$\endgroup\$
    – Tim L
    Commented Jan 30, 2018 at 4:20

1 Answer 1


Trimpots especially multi-turn pots are often numbered with pin 1 being the CCW position and 3 for CW.

Since it is not marked (as one would hope) on the schematic, you may hope what see is the minimum position is pin 1 (CCW).

This "standard" was started by Bourns and but it's hard to say if it is still universal.


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