Using LEDs as Light Sensors

In my previous article DC Versus AC I discussed how a diode can be used as a rectifier to convert alternating current (AC) into direct current (DC) because the diode allows current to flow in one direction, but not the other. The diode is the simplest semiconductor electronic component, but the physics of how they work is perhaps somewhat complicated. There are many resources available on the web such as the Edison Tech Center semiconductor resource page.