dióda

Diode (dióda) is a two-terminal electronic component that conducts current primarily in one direction. It has a nonlinear current–voltage characteristic. In forward bias, the p-n junction's depletion region narrows, allowing carriers to cross the junction; a threshold voltage, typically about 0.6–0.7 volts for silicon diodes, must be exceeded before significant current flows. In reverse bias, the depletion region widens and current is limited to a small leakage until breakdown at a high reverse voltage.

Most common diodes are made from silicon or germanium and rely on a p-n junction formed by doping one side with acceptor atoms and the other with donor atoms. Variants include Schottky diodes (metal–semiconductor junction), Zener diodes (designed to operate in reverse breakdown for regulation), and specialized diodes such as light-emitting diodes (LEDs) and photodiodes which respond to light, and varactor diodes whose capacitance varies with voltage. The performance characteristics, including forward voltage drop, reverse leakage current, switching speed, and breakdown voltage, depend on the material and construction.

Diodes are used for rectification in power supplies, signal demodulation, voltage regulation, protection against transients, and in switching and digital circuits. The concept dates to early rectifier devices, with Fleming's vacuum-tube diode introduced in 1904, and solid-state p-n junction diodes becoming widespread in the mid-20th century.