Diodien

Diodien, or diodes, are two-terminal semiconductor devices that allow electric current to flow primarily in one direction. They form the basic building block of many electronic circuits by providing rectification, switching, regulation, and protection functions. In normal operation, a diode conducts readily when forward biased (positive voltage on the anode relative to the cathode) and blocks current when reverse biased.

Most diodes are based on a PN junction and are made from silicon, germanium, or compound semiconductors. The junction creates a depletion region that acts as a barrier to charge flow. When forward biased, the barrier is reduced and charge carriers cross the junction, producing current. When reverse biased, the barrier widens and current is limited to a small leakage. Some diodes are designed to exploit controlled breakdown or other effects under reverse bias.

Common types include:

- Rectifier diodes, used to convert alternating current to direct current in power supplies.

- Schottky diodes, with low forward voltage drop and fast switching.

- Zener diodes, used for voltage regulation in reverse bias.

- Light-emitting diodes (LEDs), which emit light when forward biased.

- Photodiodes, which generate current in response to light.

- Varactor diodes, used as voltage-controlled capacitors in RF circuits.

- Avalanche diodes and TVS diodes, used for surge protection.

Key characteristics include forward voltage drop, maximum forward current, reverse breakdown voltage, and switching speed. Diodes are widely used in power electronics, radio frequency circuits, signal processing, and protection networks, often in conjunction with other semiconductor devices. The concept and variety of diodes have evolved significantly since their early 20th-century development, leading to a diverse range of specialized components.