Okay you might get this a lot around here; I'm trying to figure out the inner workings of this specific potentiometer like component. I want to get my hands on the datasheet or a similar components datasheet.

It is used to change the volume of the device in question. Rolling is infinite in both directions, it has a small click. I tried measuring it's workings with the multi-meter but I'm baffled by its working.

One click in either direction shorts all three pins. The very next click measures a 620ohm between the three pins, along with a 3.2v between pin 3 and 1/2.

I'm a real noob on electrical engineering, never came across something like this.

From left to right, pin 1-3 enter image description hereenter image description here

  • 9
    \$\begingroup\$ The silk screen identifier 'SW2' gives a clue that it is a type of switch rather than a potentiometer. \$\endgroup\$
    – HandyHowie
    Mar 13 '19 at 9:37
  • 7
    \$\begingroup\$ +1 for the excellent photographs. \$\endgroup\$
    – user98663
    Mar 13 '19 at 16:02
  • \$\begingroup\$ That's a co-incidence, I just took my mouse apart to clean mine up a bit. It still sticks though. \$\endgroup\$
    – Baldrickk
    Mar 14 '19 at 13:50

That's a rotary encoder - not a potentiometer. The encoder pulses are sent to the microcontroller which adjusts the volume of the system.

enter image description here

Figure 1. 2-bit rotary encoder waveforms. The relative phase of the signals indicates clockwise/anti-clockwise rotation and can be used by the controller to count up or down.


  • \$\begingroup\$ Thank you for your detailed explanation. It all made sense now! \$\endgroup\$ Mar 13 '19 at 9:42
  • 1
    \$\begingroup\$ @RicardoSnoek Does this answer not deserve to be marked as accepted? \$\endgroup\$
    – Red.Wave
    Mar 14 '19 at 6:18
  • \$\begingroup\$ It does! Just forgot to mark it :-) \$\endgroup\$ Mar 14 '19 at 15:02

It's a rotary encoder, rather than a potentiometer. It looks like this may be your part, but you may need to contact them to get a datasheet.


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