How come when I shine a light on an LED, I get a positive voltage?

[J0hnny]

When shining a light onto the LED surface, I get a voltage reading on my volt meter. Is the LED acting like a photovoltaic cell?

 

[J0hnny]

anyone?

 

[Oblivionaire]

Yeah pretty much. People have built laser power meters with those. Just a voltmeter and an LED, gotta calibrate it of course...

 

[neutralizer]

LEDs are diodes and IIRC, shining light on a diode will excite the electrons and change the balance of flux and diffusion of electrons so that there is a voltage. More sensitive diodes to light are photodiodes.