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Semiconductors_and_Diode_Applications.pptx
- 1. Semiconductors and Diode Applications AComprehensive Overview Intrinsic/Extrinsic Semiconductors, Diodes, and Applications
- 2. Outline • • Introductionto Semiconductors • • Intrinsic and Extrinsic Semiconductors • • Energy Band Diagrams • • PN Junction Diode and V-I Characteristics • • Zener Diode and Breakdown • • Light Emitting Diode (LED) • • Diode Applications: Rectifiers • • PIV, DC/RMS, Ripple Factor • • Voltage Regulation using Zener Diode
- 3. Introduction to Semiconductors •• Materials with conductivity between conductors and insulators • • Conductivity changes with temperature, impurities, or light • • Used in electronic devices for control and amplification
- 4. Types of Semiconductors •1. Intrinsic Semiconductors • 2. Extrinsic Semiconductors
- 5. Intrinsic Semiconductors • •Pure semiconductor material (e.g., Silicon, Germanium) • • Equal number of electrons and holes • • Conductivity depends on temperature
- 6. Extrinsic Semiconductors • •Doped with impurities to improve conductivity • • Two types: • – N-type: excess electrons • – P-type: excess holes
- 7. N-type Semiconductor • •Doped with pentavalent atoms (Phosphorus, Arsenic) • • Extra electron acts as majority carrier • • Holes are minority carriers
- 8. P-type Semiconductor • •Doped with trivalent atoms (Boron, Gallium) • • Creates holes as majority carriers • • Electrons are minority carriers
- 9. Energy Band Diagrams •• Valence Band – filled with electrons • • Conduction Band – free electrons move here • • Forbidden Energy Gap separates them • • Smaller gap → higher conductivity
- 10. PN Junction Diode •• Formed by joining P-type and N-type semiconductors • • Depletion region forms at the junction • • Allows current flow in one direction
- 11. V-I Characteristics ofDiode • • Forward Bias: current increases exponentially after threshold • • Reverse Bias: small leakage current • • Breakdown occurs at high reverse voltage
- 12. Zener Diode • •Specially designed to operate in reverse breakdown region • • Used for voltage regulation
- 13. Breakdown Mechanisms • 1.Avalanche Breakdown – due to carrier collision • 2. Zener Breakdown – due to strong electric field
- 14. Light Emitting Diode(LED) • • Forward-biased diode emits light • • Made from direct band-gap materials (e.g., GaAs, GaP) • • Color depends on band gap energy
- 15. Diode Applications –Rectifiers • • Convert AC to DC • • Types: • – Half-wave Rectifier • – Full-wave Rectifier • – Bridge Rectifier
- 16. Half-Wave Rectifier • •Uses one diode • • Conducts during one half cycle of AC • • Simple but inefficient
- 17. Full-Wave Rectifier • •Uses two diodes and center-tapped transformer • • Conducts during both halves of AC • • Higher efficiency than half-wave
- 18. Bridge Rectifier • •Uses four diodes in bridge configuration • • Eliminates need for center-tapped transformer • • Provides full-wave rectification
- 19. PIV, DC &RMS Derivation • • Peak Inverse Voltage (PIV): Maximum reverse voltage diode can withstand • • DC Output Voltage: Average value of rectified output • • RMS Value: Equivalent AC value
- 20. Ripple Factor • •Measure of residual AC in output • • Ripple Factor = Vrms / Vdc • • Lower ripple → smoother DC
- 21. Voltage Regulation usingZener Diode • • Zener diode connected in reverse bias • • Maintains constant output voltage • • Acts as voltage regulator
- 22. C Filter andRipple Reduction • • Capacitor filter smooths pulsating DC • • Capacitor charges during conduction and discharges during non-conduction • • Reduces ripple
- 23. Determination of RippleFactor • • Depends on load resistance and capacitance • • Ripple Factor (γ) = 1 / (4√3 f R_L C) • • Increasing C or R_L reduces ripple
- 24. Summary • • Semiconductorsform base of modern electronics • • Diodes used for rectification, regulation, and light emission • • Proper design ensures efficiency and stability
- 25. Applications • • Powersupplies • • Voltage regulators • • Signal processing • • LEDs in displays and indicators
Editor's Notes
- #3 Semiconductors are the foundation of modern electronics — transistors, diodes, ICs are all based on semiconductor materials like silicon and germanium.
- #5 Intrinsic semiconductors are free of impurities. At room temperature, few electrons jump from the valence band to the conduction band, creating holes.
- #6 Adding impurities introduces free charge carriers, making semiconductors more conductive and controllable.
- #9 Energy band diagrams help visualize how electrons transition from valence to conduction bands, determining material behavior.
- #12 Zener diodes maintain a constant voltage across a load even when supply voltage or load current varies.