/ˈdaɪoʊd/
noun … “Semiconductor device that allows current to flow in one direction.”
Diode is a two-terminal electronic component that permits electric current to flow primarily in a single direction while blocking it in the opposite direction. Diodes are fundamental elements in electronic circuits, used for rectification, signal shaping, protection, and voltage regulation. They are built from semiconductor materials, typically silicon, arranged to form a p–n junction.
In a Diode, current flows easily when the device is forward-biased (positive voltage applied to the p-side relative to the n-side) and is largely blocked when reverse-biased. This directional behavior makes diodes essential for converting alternating current (AC) into direct current (DC) and for protecting circuits from incorrect polarity.
Key characteristics of Diode include:
- Unidirectional conduction: current flows mainly in one direction.
- Forward voltage drop: a minimum voltage required before conduction begins.
- Reverse breakdown: maximum reverse voltage the diode can withstand.
- Fast switching: important in digital and high-frequency applications.
- Varieties: rectifier, Zener, Schottky, light-emitting (LED), and photodiode.
Common applications of Diode include power supplies, signal rectification, voltage clamping, reverse-polarity protection, and light emission in LEDs.
Workflow example: Diode rectifying an AC signal:
ac_input = alternating_voltage()
if ac_input > 0:
output = ac_input -- Diode conducts
else:
output = 0 -- Diode blocks
Here, the diode passes only the positive half of the waveform, converting AC into a pulsating DC signal.
Conceptually, a Diode is like a one-way valve in plumbing: fluid can flow forward, but reverse flow is blocked.
See Semiconductor, Transistor, Rectifier, LED, Power Supply.