Special Diode | Tunnel Diode | Varactor Diode | Shockley Diode

What is Tunnel Diode A tunnel diode is a pn junction that exhibits negative resistance between two values of forwardvoltage (i.e., between peak-point voltage and valley-point voltage). A conventional diode exhibits *positive resistance when it is forward biased or reverse biased. However, if a semiconductor junction diode is heavily doped with impurities, it exhibits negative … Read more

What is Photo diode | Operation | Applications | Optoisolator

What is Photo diode ? A photo diode is a reverse-biased silicon or germanium pn junction in which reverse current increases when the junction is exposed to light. The reverse current in a photo-diode is directly proportional to the intensity of light falling on its pn junction. This means that greater the intensity of light … Read more

What is LED (Light-Emitting Diode) | LED Voltage and Current

What is LED ? A light-emitting diode (LED) is a diode that gives off visible light when forward biased. Light-emitting diodes are not made from silicon or germanium but are made by using elements like gallium, phosphorus and arsenic. By varying the quantities of these elements, it is possible to produce light of different wavelengths … Read more