A transistor is a semiconductor device used to amplify or switch electronic signals. It’s the key component in logic gates, signal amplifiers, and voltage regulators.
How It Works:
There are two major families:
- BJT (Bipolar Junction Transistor) – controlled by current.
- FET (Field Effect Transistor) – controlled by voltage.
BJT has three terminals: Base, Collector, and Emitter.
FET has: Gate, Drain, and Source.
Types of Transistors:
- NPN & PNP BJTs: Common in analog circuits.
- MOSFETs: Widely used in digital and power electronics.
- JFETs: Voltage-controlled, used in low-noise applications.
- IGBTs: Ideal for high power control systems.
Applications:
- Audio amplification
- Motor control
- Logic circuits (digital computing)
- Voltage regulators
- Radio transmission
Key Specs:
- Gain (hFE)
- Switching speed
- Maximum current and voltage
- Saturation voltage
- Gate threshold voltage (for FETs)
Transistors are a must-know for every engineer or hobbyist, and understanding their characteristics unlocks a world of electronic design.
