
Now weβre moving to practical electronics. Iβll explain in two parts:
π 1. Applications of Diodes
π 2. Other Terminal Devices
π Applications of Diodes
Diodes are used in many electronic circuits because they allow one-way current flow.
πΉ 1. Rectification (AC β DC)
- Diodes convert AC into DC
- Used in power supplies
- Types: Half-wave & Full-wave rectifiers
π Example: Mobile charger
πΉ 2. Clipping Circuits
- Removes unwanted parts of a signal
- Protects circuits from high voltage
π Used in signal processing
πΉ 3. Clamping Circuits
- Shifts voltage level of signals
- Maintains waveform shape
π Used in TV and communication systems
πΉ 4. Voltage Regulation (Zener Diode)
- Maintains constant output voltage
- Protects devices from voltage fluctuations
πΉ 5. Light Emission (LED)
- Converts electrical energy to light
- Used in displays and indicators
πΉ 6. Detection (Demodulation)
- Extracts information from signals
- Used in radio receivers
βοΈ Other Terminal Devices
(Devices with more than two terminals used for switching/amplification)
πΈ Transistor (BJT)

π What is a Transistor?
A transistor is a three-terminal semiconductor device.
Terminals:
- Emitter
- Base
- Collector
Functions:
- Amplification
- Switching
Types:
- NPN
- PNP
π Used in amplifiers, computers, radios.
πΈ Field Effect Transistor (FET)

π What is FET?
A voltage-controlled device with three terminals:
- Gate
- Source
- Drain
Features:
- High input impedance
- Low power consumption
π Used in ICs and digital circuits.
πΈ Thyristor (SCR)

π What is SCR?
A four-layer semiconductor device used for power control.
Terminals:
- Anode
- Cathode
- Gate
Applications:
- Motor speed control
- Power regulation
- Light dimmers
π§ Quick Exam Summary
π Diodes are used for rectification, clipping, clamping, and regulation.
π Transistors amplify and switch signals.
π FETs are voltage-controlled devices.
π SCRs control high power circuits.