I removed a photosensor from an OLD hp Inkject Printer. The photosensor is called "C8941-80018". I can't find any datasheet online. Does anyone know what wire color is what? enter image description here

  • \$\begingroup\$ Green=0v is ground? \$\endgroup\$ Commented Jul 14, 2020 at 13:31
  • \$\begingroup\$ The version changes may be confusing. i.sstatic.net/7U3ub.png but Rohat has the right idea \$\endgroup\$ Commented Jul 14, 2020 at 13:59
  • \$\begingroup\$ I leave you the images of the sensor, I am trying to make a photo switch with a relay and I was looking for information so I hope the images will help you, greetings from Mexico. i.sstatic.net/JBlGF.jpg i.sstatic.net/YseiU.jpg \$\endgroup\$ Commented Oct 2, 2020 at 7:20
  • \$\begingroup\$ @Jose Please ask this as a new question. || Use the ASK QUESTION button at the top of each page. \$\endgroup\$
    – Russell McMahon
    Commented Oct 2, 2020 at 10:41

1 Answer 1


The colors differ from module to module. Some modules have Black-Green-Blue instead of White-Green-Red - At least Google Images say so.

The module itself is nothing different from a LED-Phototransistor Combo. According to your drawing, from the top-view, left side is LED (you can verify this by seeing a diode symbol on the topside) and right side is transistor. And the connection should be something like this:


simulate this circuit – Schematic created using CircuitLab

From a Google search, you can find a picture from the bottom side of the module. And this picture verifies what I've shown above:

enter image description here


  • Middle (Green) is GND because it's a common connection
  • Top (white) is LED's anode (should be positive supply through a resistor)
  • Bottom (Red) is open-collector output

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