In this episode, Karen reviews p-in junctions and talks about how they differ from other types of common diodes, such as schottky diodes, zener diodes, LEDs (light emitting diodes), laser diodes, and photodiodes. P-N junctions are considered your typical didoes. They have a p-n junction with a threshold voltage that has to be reached before current will flow through them. In silicon diodes, this is 0.7V. Once this is reached, the current will continue flowing. When hooked up backwards, in reverse bias, these diodes do not allow current to flow. If a diode is reverse bias, and it’s supplied with too much voltage, more than it’s breakdown voltage, it’ll “break-down” and current will flow through it in the wrong direction. Schottky diodes often look like typical diodes. But unlike p-n junction diodes, Schottky diodes have a metal-semiconductor junction. Silicon diodes require time for their depletion zone to grow and shrink when switching from allowing forward current to blocking reverse current. There’s a recovery time. Schottky junctions have no depletion zone. Because of their metal-semiconductor junction, Schottky diodes require virtually no recovery time and therefore have much faster switching speeds. This means they can handle switching current better and faster, which makes them useful in high frequency applications.They also have a lower forward voltage drop. Silicon diodes have a voltage drop of around 0.7V, but the voltage drop of Schottky diodes is between 0.15 V and 0.46 V. This means they lose less energy to heat, making them more efficient. Schottky diodes are not useful for all applications, as they can leak a small amount of current backwards. This could be problematic for certain circuits. While Schottky diodes can let some voltage leak through backwards, zener diodes are designed to allow current to flow in both directions. The p-n junction of zener diodes is heavily doped, only a specific voltage, the Zener voltage (Vz) can pass thro