Category:Diodes

A semiconductor device which allows electricity to flow in only one direction. They are available in a variety of sizes, types, and electrical characteristics. The diode allows electricity to flow from anode to cathode, which is called "forward biased", but will not allow any electricity to flow from cathode to anode, called "reverse biased".

Diodes can be utilised for a number of purposes, such as circuit protection (placed in a circuit to protect from an improperly installed battery) or rectification (converting AC to DC)

Types
Some diodes are classified by the semiconductor from which they are made. These typically have a forward voltage around 0.6 volts at low currents and a reverse current in the nanoamp range. Breakdown voltages can range up to several hundred volts. These have a forward voltage of about 0.25 volts and have a much higher reverse current and lower breakdown.
 * Silicon Diode
 * Germanium diodes

There are many special types of diodes that have many special characteristics:

Designed to operate in reverse breakdown and with a specific breakdown voltage.  Have a lower forward voltage than conventional diodes and switch faster as well.  Designed to have a high rate of change of junction capacitance with change of voltage in reverse bias.  In reverse bias, conducts a current proportional to light incident on the junction.  A photo diode designed to operate near reverse breakdown with an avalanche effect that results in up to about one hundred times the current produced by the incident light.  A diode that produces light when in forward bias.  A diode that emits a narrow beam of coherent light.  A photocell that produces a voltage in response to incident light. 
 * Zener diode
 * Schottky diode
 * Varicap or Varactor Diode
 * Photodiode
 * Avalanche Photodiode
 * Light Emitting Diode (LED)
 * Laser Diode
 * Photovoltaic Diode

The following do not function as described above An obsolete form of thyristor  A diode that has a region of negative dynamic resistance.  
 * Shockley diode
 * Tunnel Diode
 * Vacuum Tube Diode