In most circuits the photo diode is reverse biased, so that charge is carried by extrinsic charge carriers. The response time of a photo diode is typically 250 nano seconds.

Thankfully, Adafruit has a video that explains how they work. Diodes protect your circuits by forcing the electrical current to go in a specific direction.

Explore The Varactor (Varicap) Diode With Helpful Diagrams and Applications. Plus, Find The Varactor Circuit Symbol and Capacitance Equation. Visit Today!

The discussion of how the diodes work reminded us of a modern tutorial we just ran across this weekend. It’s a bit bizarre, but explains the PN junction in a different way than we’re ...