Semiconductor Diodes
description
Transcript of Semiconductor Diodes
![Page 1: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/1.jpg)
SEMICONDUCTOR, DIODE AND POWER SUPPLIES
CHAPTER TWO
![Page 2: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/2.jpg)
SEMICONDUCTOR
Meaning of SemiconductorNeither a conductor nor an insulator but rather halfway in between the two.The resistive properties of a semiconductor can be varied between those a conductor and those of an insulator.
![Page 3: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/3.jpg)
Three most commonly used semiconductor materials are silicon (Si), Germanium (Ge) and Carbon (C).
Si and Ge widely used in the production of solid state components.
![Page 4: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/4.jpg)
Atomic structure of (a) silicon; (b) germanium; and (c) gallium and arsenic.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 5: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/5.jpg)
Energy Level
![Page 6: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/6.jpg)
![Page 7: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/7.jpg)
Intrinsic and Extrinsic
Intrinsic- pure material: semiconductor which has a very low level of impurities.
Pure Si and Ge are poor conductor due to partially to the number of valence electrons, covalent bonding and relatively large energy gap.
Extrinsic- those semiconductor that has been subjected to doping process and no longer pure
Doping- is the process of adding impurity atoms to intrinsic Si or Ge to improve the conductivity of the semiconductor.
![Page 8: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/8.jpg)
N-Type material
N stand for negative charge of electron
N type is created by adding with five valence electron into a pure Si or Ge base.
![Page 9: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/9.jpg)
P-Type material
P stand for positive charge of holes
P created by adding with three valence electron into pure Si and Ge base
![Page 10: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/10.jpg)
PN junction
![Page 11: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/11.jpg)
A p–n junction with no external bias. (a) An internal distribution of charge; (b) a diode symbol, with the defined polarity and the current direction; (c) demonstration that the net carrier flow is zero at the external terminal of the device
when VD = 0 V.
![Page 12: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/12.jpg)
Diode
Forward-biased p–n junction. (a) Internal distribution of charge under forward-bias conditions; (b) forward-bias polarity and direction of resulting current.
![Page 13: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/13.jpg)
Forward and Reverse bias
![Page 14: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/14.jpg)
Series diode configuration.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 15: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/15.jpg)
Fig. 2.9 (a) Determining the state of the diode of Fig. 2.8; (b) substituting the equivalent model for the “on” diode of Fig. 2.9a.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 16: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/16.jpg)
Fig. 2.9 (continued) (a) Determining the state of the diode of Fig. 2.8; (b) substituting the equivalent model for the “on” diode of Fig. 2.9a.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 17: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/17.jpg)
Fig. 2.12 Substituting the equivalent model for the “off” diode of Fig. 2.10.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 18: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/18.jpg)
Fig. 2.11 Determining the state of the diode of Fig. 2.10.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 19: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/19.jpg)
Fig. 2.10 Reversing the diode of Fig. 2.8.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 20: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/20.jpg)
Fig. 2.13 Circuit for Example 2.4.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 21: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/21.jpg)
Fig. 2.14 Determining the unknown quantities for Example 2.5.
Robert L. BoylestadElectronic Devices and Circuit Theory, 9e
Copyright ©2006 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458
All rights reserved.
![Page 22: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/22.jpg)
Load line Analysis
![Page 23: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/23.jpg)
Diode Characteristic
![Page 24: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/24.jpg)
Load line and operating point
![Page 25: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/25.jpg)
Steps:
To find load line From equation V=Vd+IR,
Let Vd=0, so Id=V/R
Let Id = 0, so V=Vd Draw a straight line between these two values.
The intersection between the load line and characteristic curve is the operating point.
![Page 26: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/26.jpg)
Example 1
![Page 27: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/27.jpg)
![Page 28: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/28.jpg)
Approximate Model
![Page 29: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/29.jpg)
Ideal Diode
![Page 30: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/30.jpg)
Find the Operating Point using graphical method or network
![Page 31: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/31.jpg)
Parallel Configuration of Diode
![Page 32: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/32.jpg)
![Page 33: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/33.jpg)
Example 2
![Page 34: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/34.jpg)
![Page 35: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/35.jpg)
Example 3
![Page 36: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/36.jpg)
Solution I1 = Vk2 / 3.3k
= 0.7 / 3.3k= 0.212mA
Find V2, using KVL-V+Vk1+Vk2+V2=0
V2=V-Vk1-Vk2 = 20-0.7-0.7 = 18.6V
Find I2 using Ohm’s LawI2=V2 / R2 = 18.6 / 5.6k
=3.32mA
To find IdId=I2-I1 = 3.32mA- 0.212mA = 3.11mA
![Page 37: Semiconductor Diodes](https://reader034.fdocuments.us/reader034/viewer/2022052304/563db882550346aa9a945aa3/html5/thumbnails/37.jpg)