Gunn Diode
A Gunn diode is a special type of semiconductor device used to generate high-frequency electrical signals, especially in the microwave range.
What makes it unique?
Unlike typical diodes (like rectifiers), a Gunn diode doesn’t rely on a p–n junction. Instead, it works based on a phenomenon called the Gunn effect.
How it works
- It’s made from materials like gallium arsenide (GaAs).
- When voltage is applied, current initially increases.
- After a certain point, increasing voltage actually reduces current.
- This is called negative resistance.
- This behavior causes oscillations, producing microwave signals.
Key Features
- Generates frequencies in the GHz range
- Simple structure (no junction)
- Used as an oscillator, not a rectifier
Applications
- Radar systems (e.g., speed guns)
- Microwave transmitters
- Motion detectors
- Satellite communication systems