In this chapter, you will learn about: Zener diodes; Opto-Electronic Diodes: Light Emitting Diodes (LEDs), laser diodes, photodiodes, solar cells, varactor diodes. | Dr. Nasim Zafar Electronics 1 EEE 231 – BS Electrical Engineering Fall Semester – 2012 COMSATS Institute of Information Technology Virtual campus Islamabad Special-Purpose Diodes: Lecture No: 12 Contents: Zener diodes Opto-Electronic Diodes Light Emitting Diodes (LEDs) Laser Diodes Photodiodes Solar Cells Varactor Diodes Reference: Chapter 3 - Special-Purpose Diodes: Figures are redrawn (with some modifications) from Electronic Devices By Thomas L. Floyd Applications of PN Junctions: P N J U N C T I O N PN Junction Diode Junction Diode Rectifiers Switching Diode Zener Diode Varactor Diode Tunnel Diode Photo-Diode Light Emitting diode & Laser Diode BJT (Bipolar Junction Transistor) Solar Cell Photo Detector HBT (Heterojunction Bipolar Transistor) FET (Field Effect Transistor) JFET MOSFET - memory MESFET - HEMT 4 5 Common Applications of Diodes: Rectifier Zener LED Schematic symbol Bias for normal operation Switched back and forth between forward and reverse. Reverse Forward Normal VF Si: VF = V Ge: VF = V VF = V (not normally operated) Normal VR Equal to applied voltage. Equal to VZ. Equal to applied voltage. Primary factors to consider for device substitution I0 and VRRM ratings. PD(max) and VZ ratings. VF(min), IF(max), and VBR Types of Diodes and Their Uses PN Junction Diodes: Are used to allow current to flow in one direction while blocking current flow in the opposite direction. The PN junction diode is the typical diode that has been used in the previous circuits. A K Schematic Symbol for a PN Junction Diode P n Representative Structure for a PN Junction Diode Zener Diodes: Are specifically designed to operate under reverse breakdown conditions. These diodes have a very accurate and specific reverse breakdown voltage. A K Schematic Symbol for a Zener Diode Schottky Diodes: These diodes are designed to have a very fast switching time which makes them a great diode for digital circuit applications. They are very common in computers because of their | Dr. Nasim Zafar Electronics 1 EEE 231 – BS Electrical Engineering Fall Semester – 2012 COMSATS Institute of Information Technology Virtual campus Islamabad Special-Purpose Diodes: Lecture No: 12 Contents: Zener diodes Opto-Electronic Diodes Light Emitting Diodes (LEDs) Laser Diodes Photodiodes Solar Cells Varactor Diodes Reference: Chapter 3 - Special-Purpose Diodes: Figures are redrawn (with some modifications) from Electronic Devices By Thomas L. Floyd Applications of PN Junctions: P N J U N C T I O N PN Junction Diode Junction Diode Rectifiers Switching Diode Zener Diode Varactor Diode Tunnel Diode Photo-Diode Light Emitting diode & Laser Diode BJT (Bipolar Junction Transistor) Solar Cell Photo Detector HBT (Heterojunction Bipolar Transistor) FET (Field Effect Transistor) JFET MOSFET - memory MESFET - HEMT 4 5 Common Applications of Diodes: Rectifier Zener LED Schematic symbol Bias for normal operation Switched back and forth between forward and reverse. Reverse Forward Normal VF
