Diodes are part of the electronic components that are used today and are widely used for a number of applications. The more popular types of diodes are described below.
Diodes – A diode is a two-terminal electronic component with asymmetric conductance; it has low (ideally zero) resistance to current in one direction, and high (ideally infinite) resistance in the other.
LED – A light-emitting diode (LED) is a two-lead semiconductor light source. It is a basic pn-junction diode, which emits light when activated. When a fitting voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.
PhotoDiode – A photodiode is a semiconductor device that converts light into current. The current is generated when photons are absorbed in the photodiode. A small amount of current is also produced when no light is present. Photodiodes may contain optical filters, built-in lenses, and may have large or small surface areas. Photodiodes usually have a slower response time as its surface area increases. The common, traditional solar cell used to generate electric solar power is a large area photodiode.
Schottky Diode – The Schottky diode (named after German physicist Walter H. Schottky); also known as hot carrier diode is a semiconductor diode with a low forward voltage drop and a very fast switching action. The cat’s-whisker detectors used in the early days of wireless and metal rectifiers used in early power applications can be considered primitive Schottky diodes.
Tunnel Diode – A tunnel diode or Esaki diode is a type of semiconductor that is capable of very fast operation, well into the microwave frequency region, made possible by the use of the quantum mechanical effect called tunneling.
Varicap – A varicap diode, varactor diode, variable capacitance diode, variable reactance diode or tuning diode is a type of diode whose capacitance varies as a function of the voltage applied across its terminals.
Zener Diode – A Zener diode is a diode which allows current to flow in the forward direction in the same manner as an ideal diode, but also permits it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, “Zener knee voltage”, “Zener voltage”, “avalanche point”, or “peak inverse voltage.