I found a component, which I couldn't recognize, on a printed circuit board. Does anyone know this kind of component?

Edited :The unknown components are the white squared ones. There are many of them.

The person that ask me this didn't tell me what this circuit does.

I attached a photo to help in the recognition:

Unknown component

  • 4
    \$\begingroup\$ The array of white boxes with 4 terminals each might be optocouplers of some sort. \$\endgroup\$
    – Dave Tweed
    Commented Nov 14, 2019 at 21:06

1 Answer 1


It is an optocoupler. Confirmed by typing "3215 optocoupler" into google.

enter image description here


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