Submit Search
Upload
Lecture 08 hibridequivalentmodel
•
3 likes
•
1,544 views
I
Ismael Cayo Apaza
Follow
circuitos electronicos
Read less
Read more
Technology
Report
Share
Report
Share
1 of 11
Download now
Download to read offline
Recommended
A laboratory model of a dual active bridge dc-dc converter for a smart user n...
A laboratory model of a dual active bridge dc-dc converter for a smart user n...
Alessandro Burgio
Current mirror-A constant current circuit
Current mirror-A constant current circuit
Dr. Kapil Gupta
Power Supply Project
Power Supply Project
usmanhadi91
Chapter 5 DC-DC Converters.pdf
Chapter 5 DC-DC Converters.pdf
LiewChiaPing
Michael john sebastian smith application-specific integrated circuits-addison...
Michael john sebastian smith application-specific integrated circuits-addison...
Đình Khanh Nguyễn
Electrónica digital: Tema 3 Funciones aritméticas y lógicas
Electrónica digital: Tema 3 Funciones aritméticas y lógicas
SANTIAGO PABLO ALBERTO
Pic 18 microcontroller
Pic 18 microcontroller
Ashish Ranjan
Variable power supply
Variable power supply
Teksify
Recommended
A laboratory model of a dual active bridge dc-dc converter for a smart user n...
A laboratory model of a dual active bridge dc-dc converter for a smart user n...
Alessandro Burgio
Current mirror-A constant current circuit
Current mirror-A constant current circuit
Dr. Kapil Gupta
Power Supply Project
Power Supply Project
usmanhadi91
Chapter 5 DC-DC Converters.pdf
Chapter 5 DC-DC Converters.pdf
LiewChiaPing
Michael john sebastian smith application-specific integrated circuits-addison...
Michael john sebastian smith application-specific integrated circuits-addison...
Đình Khanh Nguyễn
Electrónica digital: Tema 3 Funciones aritméticas y lógicas
Electrónica digital: Tema 3 Funciones aritméticas y lógicas
SANTIAGO PABLO ALBERTO
Pic 18 microcontroller
Pic 18 microcontroller
Ashish Ranjan
Variable power supply
Variable power supply
Teksify
Ic voltage regulators
Ic voltage regulators
Anita Thattil
Transformateur
Transformateur
Salif Kagone
Amp400wt8
Amp400wt8
ninguna
Rectifiers and Filter Circuits
Rectifiers and Filter Circuits
Rakesh Sheoran
Forward convertor
Forward convertor
zeshana
Differential amplifier
Differential amplifier
Arpit Raval
Eca unit 2
Eca unit 2
Pavan Mukku
Tda 90w mono
Tda 90w mono
Francisco Torres Herrera
Semiconductor diodes
Semiconductor diodes
priyanka singh
Circuitiraddrizzatori 1
Circuitiraddrizzatori 1
torregan
Flyback converter
Flyback converter
Hassan Khalid Uppal
2 port network
2 port network
mihir jain
Opto Couplers – Types & Applications
Opto Couplers – Types & Applications
elprocus
Les Appareils De DéPart Moteurs Diapo
Les Appareils De DéPart Moteurs Diapo
youri59490
Exemple d'installation électrique.pdf
Exemple d'installation électrique.pdf
WalidBM1
Electrónica de potencia
Electrónica de potencia
andres
Invering and non inverting amplifiers
Invering and non inverting amplifiers
Muhammad Mohsin
Polycopié Electronique de puissance avec Matlab Simulink.pdf
Polycopié Electronique de puissance avec Matlab Simulink.pdf
YoussefOumhella
Cuk dc dc+converter
Cuk dc dc+converter
Air University
Lecture 07 transistor re model
Lecture 07 transistor re model
Ismael Cayo Apaza
h parameter conversion formulas
h parameter conversion formulas
Sadeesh Kalhara
Chap7part4 (2)
Chap7part4 (2)
Hmadi Mossoi
More Related Content
What's hot
Ic voltage regulators
Ic voltage regulators
Anita Thattil
Transformateur
Transformateur
Salif Kagone
Amp400wt8
Amp400wt8
ninguna
Rectifiers and Filter Circuits
Rectifiers and Filter Circuits
Rakesh Sheoran
Forward convertor
Forward convertor
zeshana
Differential amplifier
Differential amplifier
Arpit Raval
Eca unit 2
Eca unit 2
Pavan Mukku
Tda 90w mono
Tda 90w mono
Francisco Torres Herrera
Semiconductor diodes
Semiconductor diodes
priyanka singh
Circuitiraddrizzatori 1
Circuitiraddrizzatori 1
torregan
Flyback converter
Flyback converter
Hassan Khalid Uppal
2 port network
2 port network
mihir jain
Opto Couplers – Types & Applications
Opto Couplers – Types & Applications
elprocus
Les Appareils De DéPart Moteurs Diapo
Les Appareils De DéPart Moteurs Diapo
youri59490
Exemple d'installation électrique.pdf
Exemple d'installation électrique.pdf
WalidBM1
Electrónica de potencia
Electrónica de potencia
andres
Invering and non inverting amplifiers
Invering and non inverting amplifiers
Muhammad Mohsin
Polycopié Electronique de puissance avec Matlab Simulink.pdf
Polycopié Electronique de puissance avec Matlab Simulink.pdf
YoussefOumhella
Cuk dc dc+converter
Cuk dc dc+converter
Air University
Lecture 07 transistor re model
Lecture 07 transistor re model
Ismael Cayo Apaza
What's hot
(20)
Ic voltage regulators
Ic voltage regulators
Transformateur
Transformateur
Amp400wt8
Amp400wt8
Rectifiers and Filter Circuits
Rectifiers and Filter Circuits
Forward convertor
Forward convertor
Differential amplifier
Differential amplifier
Eca unit 2
Eca unit 2
Tda 90w mono
Tda 90w mono
Semiconductor diodes
Semiconductor diodes
Circuitiraddrizzatori 1
Circuitiraddrizzatori 1
Flyback converter
Flyback converter
2 port network
2 port network
Opto Couplers – Types & Applications
Opto Couplers – Types & Applications
Les Appareils De DéPart Moteurs Diapo
Les Appareils De DéPart Moteurs Diapo
Exemple d'installation électrique.pdf
Exemple d'installation électrique.pdf
Electrónica de potencia
Electrónica de potencia
Invering and non inverting amplifiers
Invering and non inverting amplifiers
Polycopié Electronique de puissance avec Matlab Simulink.pdf
Polycopié Electronique de puissance avec Matlab Simulink.pdf
Cuk dc dc+converter
Cuk dc dc+converter
Lecture 07 transistor re model
Lecture 07 transistor re model
Viewers also liked
h parameter conversion formulas
h parameter conversion formulas
Sadeesh Kalhara
Chap7part4 (2)
Chap7part4 (2)
Hmadi Mossoi
Hybrid model analog electronics
Hybrid model analog electronics
rakesh mandiya
Transistor at high Frequency ACD ppt
Transistor at high Frequency ACD ppt
sanjaytron
CE, CB, CC AMPLIFIERS
CE, CB, CC AMPLIFIERS
bharath405
Bipolar Junction Transistor
Bipolar Junction Transistor
Yong Heui Cho
Viewers also liked
(6)
h parameter conversion formulas
h parameter conversion formulas
Chap7part4 (2)
Chap7part4 (2)
Hybrid model analog electronics
Hybrid model analog electronics
Transistor at high Frequency ACD ppt
Transistor at high Frequency ACD ppt
CE, CB, CC AMPLIFIERS
CE, CB, CC AMPLIFIERS
Bipolar Junction Transistor
Bipolar Junction Transistor
Similar to Lecture 08 hibridequivalentmodel
Hybrid Transistor Model with Two Port Network
Hybrid Transistor Model with Two Port Network
Ridwanul Hoque
Hybrid model for Transistor, small signal Analysis
Hybrid model for Transistor, small signal Analysis
Abhishek Choksi
electronic-circuits_unit-4 small signal analysis.ppt
electronic-circuits_unit-4 small signal analysis.ppt
LAXMAREDDY22
NAS-Unit-5_Two Port Networks
NAS-Unit-5_Two Port Networks
Hussain K
Lecture 11.pptx
Lecture 11.pptx
AhmedSheikAliAdan
Ec8353 edc unit3
Ec8353 edc unit3
elakkia8
Chapter02
Chapter02
vikram anand
Microelectronic circuits and devices: chapter one
Microelectronic circuits and devices: chapter one
muhabaw amare
Small signal analysis based closed loop control of buck converter
Small signal analysis based closed loop control of buck converter
Ramaraochowdary Kantipudi
L-24(DK&SSG)(PE) ((EE)NPTEL) (4 files merged).pdf
L-24(DK&SSG)(PE) ((EE)NPTEL) (4 files merged).pdf
satyam jha
Physica curckts
Physica curckts
12B-129-El
Performance Comparison of Multi Input Capacitor Converter Circuits
Performance Comparison of Multi Input Capacitor Converter Circuits
IJECEIAES
Edc unit 2
Edc unit 2
Mukund Gandrakota
Edcqnaunit 2
Edcqnaunit 2
SRR Govt. Degree & PG College
Chapter 13 – Circuit Analysis using Laplace Transforms.pptx
Chapter 13 – Circuit Analysis using Laplace Transforms.pptx
NgcViCao
Two port network
Two port network
kaushal boghani
A Single Switch High Gain Coupled Inductor Boost Converter
A Single Switch High Gain Coupled Inductor Boost Converter
IRJET Journal
EC8353 ELECTRONIC DEVICES AND CIRCUITS Unit 3
EC8353 ELECTRONIC DEVICES AND CIRCUITS Unit 3
RMK ENGINEERING COLLEGE, CHENNAI
November 21, 20131How a Diode WorksA diode is an electrica.docx
November 21, 20131How a Diode WorksA diode is an electrica.docx
henrymartin15260
Electrical Engineering - 2006 Unsolved Paper
Electrical Engineering - 2006 Unsolved Paper
Vasista Vinuthan
Similar to Lecture 08 hibridequivalentmodel
(20)
Hybrid Transistor Model with Two Port Network
Hybrid Transistor Model with Two Port Network
Hybrid model for Transistor, small signal Analysis
Hybrid model for Transistor, small signal Analysis
electronic-circuits_unit-4 small signal analysis.ppt
electronic-circuits_unit-4 small signal analysis.ppt
NAS-Unit-5_Two Port Networks
NAS-Unit-5_Two Port Networks
Lecture 11.pptx
Lecture 11.pptx
Ec8353 edc unit3
Ec8353 edc unit3
Chapter02
Chapter02
Microelectronic circuits and devices: chapter one
Microelectronic circuits and devices: chapter one
Small signal analysis based closed loop control of buck converter
Small signal analysis based closed loop control of buck converter
L-24(DK&SSG)(PE) ((EE)NPTEL) (4 files merged).pdf
L-24(DK&SSG)(PE) ((EE)NPTEL) (4 files merged).pdf
Physica curckts
Physica curckts
Performance Comparison of Multi Input Capacitor Converter Circuits
Performance Comparison of Multi Input Capacitor Converter Circuits
Edc unit 2
Edc unit 2
Edcqnaunit 2
Edcqnaunit 2
Chapter 13 – Circuit Analysis using Laplace Transforms.pptx
Chapter 13 – Circuit Analysis using Laplace Transforms.pptx
Two port network
Two port network
A Single Switch High Gain Coupled Inductor Boost Converter
A Single Switch High Gain Coupled Inductor Boost Converter
EC8353 ELECTRONIC DEVICES AND CIRCUITS Unit 3
EC8353 ELECTRONIC DEVICES AND CIRCUITS Unit 3
November 21, 20131How a Diode WorksA diode is an electrica.docx
November 21, 20131How a Diode WorksA diode is an electrica.docx
Electrical Engineering - 2006 Unsolved Paper
Electrical Engineering - 2006 Unsolved Paper
More from Ismael Cayo Apaza
Problema sust y eolica
Problema sust y eolica
Ismael Cayo Apaza
Eer tema 03 energia solar fotovoltaica.ppt [modo de compatibilidad]
Eer tema 03 energia solar fotovoltaica.ppt [modo de compatibilidad]
Ismael Cayo Apaza
Eer tema 01 generalidades
Eer tema 01 generalidades
Ismael Cayo Apaza
El principito
El principito
Ismael Cayo Apaza
Segundo cultura nazca
Segundo cultura nazca
Ismael Cayo Apaza
La fuente
La fuente
Ismael Cayo Apaza
Aparamenta electrica.
Aparamenta electrica.
Ismael Cayo Apaza
Conductores
Conductores
Ismael Cayo Apaza
Secciontecnica
Secciontecnica
Ismael Cayo Apaza
Manual electrico viakon capitulo 2
Manual electrico viakon capitulo 2
Ismael Cayo Apaza
37. secciones 370-alarmas contra incendio
37. secciones 370-alarmas contra incendio
Ismael Cayo Apaza
Aprueban norma técnica
Aprueban norma técnica
Ismael Cayo Apaza
Conductores electricos
Conductores electricos
Ismael Cayo Apaza
Aprueban norma técnica
Aprueban norma técnica
Ismael Cayo Apaza
Elec ch06bjt amplifiers
Elec ch06bjt amplifiers
Ismael Cayo Apaza
1. el amplificador de emisor comun
1. el amplificador de emisor comun
Ismael Cayo Apaza
Lecture 06 transistorremodel
Lecture 06 transistorremodel
Ismael Cayo Apaza
Practica3
Practica3
Ismael Cayo Apaza
Trabajo tercera ley d ela termodianamica
Trabajo tercera ley d ela termodianamica
Ismael Cayo Apaza
Medidas de valores máximos
Medidas de valores máximos
Ismael Cayo Apaza
More from Ismael Cayo Apaza
(20)
Problema sust y eolica
Problema sust y eolica
Eer tema 03 energia solar fotovoltaica.ppt [modo de compatibilidad]
Eer tema 03 energia solar fotovoltaica.ppt [modo de compatibilidad]
Eer tema 01 generalidades
Eer tema 01 generalidades
El principito
El principito
Segundo cultura nazca
Segundo cultura nazca
La fuente
La fuente
Aparamenta electrica.
Aparamenta electrica.
Conductores
Conductores
Secciontecnica
Secciontecnica
Manual electrico viakon capitulo 2
Manual electrico viakon capitulo 2
37. secciones 370-alarmas contra incendio
37. secciones 370-alarmas contra incendio
Aprueban norma técnica
Aprueban norma técnica
Conductores electricos
Conductores electricos
Aprueban norma técnica
Aprueban norma técnica
Elec ch06bjt amplifiers
Elec ch06bjt amplifiers
1. el amplificador de emisor comun
1. el amplificador de emisor comun
Lecture 06 transistorremodel
Lecture 06 transistorremodel
Practica3
Practica3
Trabajo tercera ley d ela termodianamica
Trabajo tercera ley d ela termodianamica
Medidas de valores máximos
Medidas de valores máximos
Recently uploaded
Ensuring Technical Readiness For Copilot in Microsoft 365
Ensuring Technical Readiness For Copilot in Microsoft 365
2toLead Limited
APIForce Zurich 5 April Automation LPDG
APIForce Zurich 5 April Automation LPDG
MarianaLemus7
Commit 2024 - Secret Management made easy
Commit 2024 - Secret Management made easy
Alfredo García Lavilla
Pigging Solutions in Pet Food Manufacturing
Pigging Solutions in Pet Food Manufacturing
Pigging Solutions
Streamlining Python Development: A Guide to a Modern Project Setup
Streamlining Python Development: A Guide to a Modern Project Setup
Florian Wilhelm
My Hashitalk Indonesia April 2024 Presentation
My Hashitalk Indonesia April 2024 Presentation
Ridwan Fadjar
SAP Build Work Zone - Overview L2-L3.pptx
SAP Build Work Zone - Overview L2-L3.pptx
NavinnSomaal
CloudStudio User manual (basic edition):
CloudStudio User manual (basic edition):
comworks
"Federated learning: out of reach no matter how close",Oleksandr Lapshyn
"Federated learning: out of reach no matter how close",Oleksandr Lapshyn
Fwdays
Nell’iperspazio con Rocket: il Framework Web di Rust!
Nell’iperspazio con Rocket: il Framework Web di Rust!
Commit University
costume and set research powerpoint presentation
costume and set research powerpoint presentation
phoebematthew05
Hot Sexy call girls in Panjabi Bagh 🔝 9953056974 🔝 Delhi escort Service
Hot Sexy call girls in Panjabi Bagh 🔝 9953056974 🔝 Delhi escort Service
9953056974 Low Rate Call Girls In Saket, Delhi NCR
"Debugging python applications inside k8s environment", Andrii Soldatenko
"Debugging python applications inside k8s environment", Andrii Soldatenko
Fwdays
Artificial intelligence in cctv survelliance.pptx
Artificial intelligence in cctv survelliance.pptx
hariprasad279825
SIP trunking in Janus @ Kamailio World 2024
SIP trunking in Janus @ Kamailio World 2024
Lorenzo Miniero
Understanding the Laravel MVC Architecture
Understanding the Laravel MVC Architecture
Pixlogix Infotech
Dev Dives: Streamline document processing with UiPath Studio Web
Dev Dives: Streamline document processing with UiPath Studio Web
UiPathCommunity
Bun (KitWorks Team Study 노별마루 발표 2024.4.22)
Bun (KitWorks Team Study 노별마루 발표 2024.4.22)
Wonjun Hwang
Vertex AI Gemini Prompt Engineering Tips
Vertex AI Gemini Prompt Engineering Tips
Miki Katsuragi
AI as an Interface for Commercial Buildings
AI as an Interface for Commercial Buildings
Memoori
Recently uploaded
(20)
Ensuring Technical Readiness For Copilot in Microsoft 365
Ensuring Technical Readiness For Copilot in Microsoft 365
APIForce Zurich 5 April Automation LPDG
APIForce Zurich 5 April Automation LPDG
Commit 2024 - Secret Management made easy
Commit 2024 - Secret Management made easy
Pigging Solutions in Pet Food Manufacturing
Pigging Solutions in Pet Food Manufacturing
Streamlining Python Development: A Guide to a Modern Project Setup
Streamlining Python Development: A Guide to a Modern Project Setup
My Hashitalk Indonesia April 2024 Presentation
My Hashitalk Indonesia April 2024 Presentation
SAP Build Work Zone - Overview L2-L3.pptx
SAP Build Work Zone - Overview L2-L3.pptx
CloudStudio User manual (basic edition):
CloudStudio User manual (basic edition):
"Federated learning: out of reach no matter how close",Oleksandr Lapshyn
"Federated learning: out of reach no matter how close",Oleksandr Lapshyn
Nell’iperspazio con Rocket: il Framework Web di Rust!
Nell’iperspazio con Rocket: il Framework Web di Rust!
costume and set research powerpoint presentation
costume and set research powerpoint presentation
Hot Sexy call girls in Panjabi Bagh 🔝 9953056974 🔝 Delhi escort Service
Hot Sexy call girls in Panjabi Bagh 🔝 9953056974 🔝 Delhi escort Service
"Debugging python applications inside k8s environment", Andrii Soldatenko
"Debugging python applications inside k8s environment", Andrii Soldatenko
Artificial intelligence in cctv survelliance.pptx
Artificial intelligence in cctv survelliance.pptx
SIP trunking in Janus @ Kamailio World 2024
SIP trunking in Janus @ Kamailio World 2024
Understanding the Laravel MVC Architecture
Understanding the Laravel MVC Architecture
Dev Dives: Streamline document processing with UiPath Studio Web
Dev Dives: Streamline document processing with UiPath Studio Web
Bun (KitWorks Team Study 노별마루 발표 2024.4.22)
Bun (KitWorks Team Study 노별마루 발표 2024.4.22)
Vertex AI Gemini Prompt Engineering Tips
Vertex AI Gemini Prompt Engineering Tips
AI as an Interface for Commercial Buildings
AI as an Interface for Commercial Buildings
Lecture 08 hibridequivalentmodel
1.
30 4A.273 © Copy
Right: Rai University ELECTRONICDESIGNTECHNOLOGY Objective : To understand the Hybrid Equivalent model of Transistor. Hello! Students I hope now you are well versed with the concepts of transistor re -model and the different configuration that we have studied in the last lectures. Now in today’s class we are going to discuss the hybrid-model for the various configura- tion. To analyze the behavior of transistor amplifier with the help of β and the values of resistances used in the circuit, is not so accurate. It is because the input and output circuits of the amplifier are considered to be completely independent and some of the effects are ignored such as IC is taken as constant but actually its value depends upon load resistance. Therefore, more accurate method to analyze a transistor amplifier is hybrid parameters (h- parameters) method, we can study h-parameter at low frequency and at high frequency. So this chapter first introduces h- parameter at low frequency and at high frequency. So this chapter first introduces h – parameter at low frequency and after that hybrid-π model (for high fre- quency). Hybrid Parameters (For Low Frequency) The four * parameters which are used to analyze any linear circuit having input and output terminals are called hybrid or h-parameters. Meaning of hybrid is ‘mixed’. Since these parameters have mixed dimensions, they are called hybrid-parameters. Determination of h-parameters Consider a linear circuit having two input and two output terminals (See Fig. 2.29). Their input and output voltage and currents are labeled with their positive directions. The conven- tions used are the standard one which may not correspond to the actual directions. However, while analyzing the circuit, if any direction is opposite that may be considered as negative. LINEAR CIRCUIT Fig. 2.29 In Fig. 4.1, the voltages and currents can be related by the following set of equations: v1 = h11 i1 + h12 v2 . …(i) i2 = h21 i1 + h22 v2 . …(ii) Where h11 , h21 , h12 and h22 are fixed constants and are known as hybrid-parameters. These parameters relate the four variables i.e. i1, i2 , v1 and v2 by the above-said two equations. If we look at the equation. (i), it is clear that h11 has the dimen- sion of ohm whereas h12 , has no dimension. Similarly, if we look at the eqn.. (ii), h2l has no dimension but h22 , has the dimension of mho. Hence, the four parameters are named as hybrid (having mixed dimensions) parameters. These parameters can be determined very easily as explained below: (i) Short-circuit the output terminals, as shown in Fig. 2.30(a), the output voltage reduces to zero i.e. v2 , = 0. Substituting this value in eqns. (i) and (ii). we get v1 = h11 + h12 × 0 Fig. 2.30 (a) and (b) or h11 = 1 1 t v (output short circuited; v2 = 0) ….(iii) and t2 = h21 i1 + h22 × 0 or h21 = 1 2 i i (output short circuited; v2 = 0) ….(iv) Here, h11 is called input impedance (i.e. v1 / ii ) with output shorted and h2l is called current gain (i.e. i2 ./ i1 ) with output shorted. (ii) Open circuit the input terminals, as shown in Fig. 2.30b, the input current reduces to zero i.e. i1 = 0. Substituting this value in eqns. (i) and (ii), we get, v1 = h11× 0 + h12 v2 or h12 = 2 1 v v (input opened; i1 = 0) ….(v) and i2 = h21 × 0 + h22 v2 or h22 = 2 2 v i (input opened; i1 = 0) ….(vi) Here, h12 is called voltage feedback ratio (i.e. v1 /v2 ) with input terminals open and h2 is called output admittance (i.e.i2 / v2 ) with input terminal open. LESSON 8: (HYBRID EQUIVALENT MODEL) UNIT - 2 (SMALL SIGNAL ANALYSIS FOR BJT : SINGLE STAGE AND MULTISTAGE AMPLIFIER)
2.
© Copy Right:
Rai University 4A.273 31 ELECTRONICDESIGNTECHNOLOGY Hybrid-Parameter Equivalent Circuit Fig. 2.31 &2.32 A two port linear circuit is shown in Fig. 2.31. The voltages and currents of the circuit can be expressed in terms of h-parameters by the expressions; V1= h11 i1 + h12 v2 ...(i) i,2 = h21 i1 + h22 v2 ...(ii) The h-parameters’ equivalent circuit is shown in Fig. 2.32. The input circuit (or port) is derived from the exp. (i). Here, input impedance (resistor) h is connected in series with a voltage generator h12 v2 . The output circuit (or port) is derived from exp. (ii) it involves current generator h2l v2. and shunt resistor h22 . Example.1 Determine the h-parameters of the circuit shown in Fig. 2.33. Fig. 2.33 & 2.34 Solution. To determine h- parameters of the circuit proceed as follows: (i) Short-circuit the output terminals as shown in fig 2.34 can determine h11 and h21 . Since 10 Ω resistor is short circuited h11 = 2 Ω Now, current i1 flows into the box and the same current flows out of the box. ∴ i2 = i1 . And h21 = 1 1 1 1 2 −= − = i i i i (ii) Open the input terminals and make the arrangement as shown in Fig. 2.35. It may be noted that output terminals are driven by voltage v2 and no current flows through 20 Ωresistor. Hence, the voltage across 10 Ω resistor i.e. v2 reaches across the input terminals. ∴ v1 = v2 Figure 2.36 and 1 2 2 2 1 == v v v v Output impedance = 10 Ω ∴ Output impedance, h22 = 01.0 10 1 mh= Hence the various h-parameters of the circuit are h11 = 20 Ω; h21 = -1 h12 = 1; h12 = 0.1 mho Example.2 To determine the h-parameter of the circuit shown in Fig 2.36 Solution. To determine h- parameters of the circuit proceed as follows: (i) Short circuit the output terminals as shown in Fig. 4.10. h11 = 6 + 8 | | 8 = 6 + = + × 88 88 10Ω Now, the input current i1 is divided equally at the junction. Fig.2.36 ∴ i2 = 1 1 5.0 2 i i −=− h21 = 5.0 5.0 1 1 1 2 −=−=− i i i i
3.
32 4A.273 © Copy
Right: Rai University ELECTRONICDESIGNTECHNOLOGY Fig.2.37&2.38 (ii) Open the input terminals and make the arrangement as shown in Fig. 2.38. Here, no current flows through 6 il resistor as the output terminals are driven by voltage v2 . v1 = 2 22 5.08 16 8 88 v vv =×=× + ∴ h12 = 5.0 5.0 2 1 2 2 == v v v v Impedance looking into the output terminals = 8 + 8 = 16 Ω h22 = 16 1 = 0.0625 mho Hence, the various h-parameters of the circuit are h11 . = 10 Ω ; h21 = - 0.5 ; h12 = 0.5 ; h22 = 0.0625 mho Performance of a Linear Circuit In H- Parameters It has already been seen that a linear circuit has a set of h- parameters. Now, we shall study the performance of such a circuit by developing expressions for input impedance, current gain, voltage gain etc. in terms of h-parameters. Figure 2.40 Consider a circuit having load resistance RL across its output terminal as shown in Fig. 2.39. Input Impedance The ratio of input voltage to input current is called the input impedance Zin . ∴ Zin.= i i i v or Zin.= 1 212111 i vhih + (∴ v1= h11 i1 + h12 v2) or Zin. = h11 + 1 212 i vh ….(i) Now, i2 = h21 i1 + h22 v2 or − =∴+= − LL i v ivhih i v 2* 2222121 2 or -h21 i1 = v2 = + L r h 1 22 The ratio of output current to input current is called current gain Ai . Zin = h11 - Lr h hh 1 22 2112 + …..(iii) We know, i2 = h21 i1 + h22 v2 and v2 = -i2 RL . (from output circuit) i2 = h21 i1 + h22 (-i2 RL ) i2 = h21 i1 + h22 rL i2 . or i2 (1 + h22 RL) = h21 i1. or Lrh h i i 22 21 1 2 1+ = Substituting the value of 1 2 i i in eqn.(iv), we get, A1 = Lrh h 22 21 1+ …..(v) If h22 rL << 1 then Ai ≅ h21 . Voltage Gain The ratio of output to input voltage is called voltage gain Av . Av = 1 2 v v ……(vi) or Av = in zi v 1 2 ( )11 inZiv =Θ
4.
© Copy Right:
Rai University 4A.273 33 ELECTRONICDESIGNTECHNOLOGY Substituting the value of 1 2 i v from eqn. (ii), we get, Av = in L Z r h h + − 1 22 21 H- Parameters of a Transistor A transistor in a three–terminal device. If any one of the terminals is made common to the input and output, it will have two ports. Thus it will have two input terminals and two output terminals (See Fig.2.40), for a small ac signal transistor behave as a linear device, hence it can be described in terms of h- parameters. The voltages and currents of the circuit can be related by the following sets of equations: Figure 2.40 V1 = h11 i1 + h12 v2 ….(i) i2 = h21 i1 + h22 v2 ….(ii) where the various h-parameters are; h11 = 1 1 i v 02=v = Input impedance (with output shorted) = hi (in ohms) h21 = 02 1 2 =v i i = Forward current ratio (with output shorted) = hf (no unit) h12 = 01 2 1 =i v v = Reverse voltage ratio (with input open)= hr (no unit) h22 = 01 2 2 =i v i = Output admittance (with input open=* h0 (in mho) While considering the behaviour of ransistor in terms of h- parameters, the following points need attention: i) The value of h-parameters of transistor will depand upon the transistor connection (i.e. CE, CB or CC). Therefore. h- parameters for different connections are abbreviated in different way. For instance, h11 is represented as **hie , hib and hic for CE, CB and CC connections. ii) While checking the performance, ac output resistance is considered as load resistance i.e. LC LC LCACL RR RR RRRr + === The values of h-parameters depend upon the Q point. If Q point changes, the values of h-parameters are also changed. In transistor circuits the values of voltage and currents are taken depending upon transistor configuration. For example, for CE configuration cce bbe IiVv IiVv == == 22 11 ; ; where Vbe, Ib, Vce and Ic are the rms values. The nomenclature used for the h-parameters of a transistor depending upon its connections is given in the following table 4.1. Table 2.1 S.No. h-parameters CE Configuration CB Configuration CC Configuration 1 h11 hie hib hie 2 h12 hre hrb hrc 3 h21 hfe hfb hfc 4 h22 h0e h0b h0c The typical values of h-parameters of a 2N 3904 transistor are given below: hie = 3.5 k Ω; hre =1.3 x 10-4 hfe = 120; hoe = 8.5 µ mho *It may be noticed that subscript used is the first letter of the description i.e. input, forward, reverse and output respectively. ** It may be noticed that the second letter of the subscript used indicates the type of transistor connections. Performance of (Ce Circuit) Transistor in H-Parameters While studying the performance of a transistor, we are inter- ested in the following terms: i) Input Impedance The general expression for Zin is L in r h hh hZ 1 22 2112 11 + −= Substituting the values of h-parameters for transistor in CE configuration. We get,
5.
34 4A.273 © Copy
Right: Rai University ELECTRONICDESIGNTECHNOLOGY L e fere iein r h hh hZ 1 0 + −= (ii) Current gain The general expression is L i rh h A 22 21 1+ = Substituting the values of h-parameters for transistor in CE configuration, we get, Le fe i rh n A 01+ = (iii) Voltage gain The general expression is in L v Z r h h A + − = 1 22 21 Substituting the values of h-parameters for transistor in CE configuration, we get, in L e fe v Z r h h A + − = 1 0 The expressions for Zin Ai and Av for other transistor connec- tions (i.e.CB and CC) can be obtained similarly. Example.3 An amplifier circuit is shown in Fig. 2.41. Work out the following quantities for the circuit: i) ac emitter current ii) ac voltage at emitter, based and collector iii) voltage gain. Assume hie or rin =250 W Figure 2.41 Solution. (i) Base current due to signal ib = )(20 250 5 valuepeakA mV r v in in µ= Ω = Collection current due to signal (peak value) mAAAii bc 110002050 ==×== µµβ Emitter current due to signal (peak value) mAmAAiii bce 102.11020201000 ≅==+=+= µ (ii) ac voltage at emitter, 0=ev (since it is connected to earth through CE ) )(5 peakmVvb = VkmARiRiv ccACcc 111 =Ω×=×== (iv) Voltage gain, Av = .200 5 1 === mV V v v v v in c in out Example.4 A single stage amplifier circuit using transistor AC 126 is shown in Fig. 2.42. Draw its ac equivalent circuit and calculate the voltage gain with an without RL . Assume the following transistor parameters: Ω== krorhorh inieacfe 5.1;150β Figure 2.42
6.
© Copy Right:
Rai University 4A.273 35 ELECTRONICDESIGNTECHNOLOGY Solution. To draw the ac equivalent circuit of an amplifier the dc voltages and capacitors are short circuited. Thus, the resultant ac equivalent circuit is shown in Fig. 2.43. Let the ac base current due to signal be 10 mA,i.e. andAib µ10= signal voltage, mVkAriv inbin 155.110 =Ω×=×= µ Collector current, mAAii bc 5.1150010150 ==×=×= µβ Output voltage, Lcout riv ×= (i) When load resistance RL is considered rL = RAC = RC || RL = Ω= + × k5.0 11 11 VkmAvout 75.05.05.1 =Ω×=∴ Voltage gain, 50 1015 75.0 15 75.0 3 = × === − mV V v v A in out v (ii) When load resistance RL is not considered rL = RC = 1kW VkmAvout 5.115.1 =Ω×=∴ Voltage gain, .100 15 5.1 === mV V v v A in out v Example. 5 A CE amplifier has the following h-parameters: 4 105.2,1100 − ×== reie hohmh mhomicrohh oefe 25,50 == If the load and source resistance both are 1 Kilo-ohm, find current and voltage gain. Solution: Here Rs =1kW and rL = 1kW= Ω× 3 101 Current gain, Ai = Loe fe Rh h ×+1 36 10110251 50 ×××+ = − = 78.48 025.01 50 = + Voltage gain, inoe fe v Z rL h h A + − = 1 Where Zin = 36 4 1011025 50105.2 1100 1 −− − ×+× ×× −= + − L oe fere ie r h hh h =100-12.5=1087.5W 977.45 5.1087)1011025( 50 36 −= ××+× − =∴ −−vA The negative sign shows that the output voltage is 1800 out of phase to the input signal. Example.6. A transistor amplifier circuit is shown in Fig. 4.17. The h-parameters of the transistor are as under. hie = 1500W ; hfe = 100 hre =4 mhohoe 44 104;10 −− ×=× Determine the ac input impedance of the amplifier and the voltage gain. Figure 2.44
7.
36 4A.273 © Copy
Right: Rai University ELECTRONICDESIGNTECHNOLOGY Solution. At load resistance of the amplifier, rL = Ω=Ω= + × = 80008 4010 4010 kRAC Input impedance, Zin = L oe fere ie r h hh h 1 + − = Ω= +× ×× − − − 1424 8000 1 104 100104 1500 4 4 AC input resistance of the entire stage *(Rac ) = Zin | | R1 | | R2 =1424 | | 100 Ω=×× 1366100050||1000 Voltage gain, Av = 134 1424 8000 1 104 100 1 4 −= +× − = + − − in L oe fe Z r h h The magnitude of gain is 134 but the output is 1800 out of phase to the input signal. Experimental Determination of Transistor H-parameters For the determination of transistor h-parameters, consider the circuit shown in Fig. 2.45. The standard equations for linear circuit are 2121111 vhihv += 2221212 vhihi += Taking rms values of voltages and currents and using standard transistor nomenclature, the above equations cab ne written as cerebiebe VhihV += … (i) cecebfec VhihI += ….(ii) Determination of hfe and hie Short circuit the output as showing in Fig. 2.46. This is accomplished by making the capacitor C2 deliberately of large value so that it can carry the short circuit current. This makes *Vce = 0 Fig.2.45 *Vce = 0 means only ac output is zero. It does not effect the dc collection to emitter voltage VCE Substituting this value in equa. (i) and (ii), we get, 0×+= rebiebe hIhV or b be ie I V h = ….(iii) 0×+= oebfec hIhI or b c fe I I h = …..(iv) Determination of hre and hoe Open circuit the input ( no signal is applied) as shown in Fig. 4.20 but a signal generator is applied across the output. Measure Vbe, Vce and Ic. . The large reactance connected in the base circuit does not allow the ac current to enter base resistor RB . At the same time reactor has a low resistance so that may not affect the operating point. Under this condition Ib =0
8.
© Copy Right:
Rai University 4A.273 37 ELECTRONICDESIGNTECHNOLOGY Substituting this value in eqns. (i) and (ii), we get, cereiebe VhhV ×+×= 0 or ce be re V V h = …(v) ceoefec VhhI ×+×= 0 or ce c oe V I h = ….(vi) Figure 2.47 Example.7 In a CE amplifier circuit, the following quantities are measured: i) When ac output is short circuited (i.e Vce =0) mVVmAIAI becb 15;5.1;15 === µ ii) When ac input is opened (i.e., Ib =0) VVAImVV cecbe 5.1;90;1 === µ Determine all the h-parameters of the circuit. Assuming that all the values are ac rms. Solution. The various h-parameters are calculated as under: Ω=== 1000 15 15 A mV I V h b be ie µ Ω=== 100 5.1 5.1 A mV I I h b c fe µ 3 1066.0 5.1 1 − ×=== A mV I V h b be re µ mho V A V I h ce c oe µ µ 60 15 90 === Approximate Analysis For a typical transistor RC = 1K and hoe =25mS CC oe oe RR h K h ≈ = || 1 40 1 Θ hence ∴ hoe may be neglected. Also , hre =2.5 4 10− × Figure 2.49a Common Emitter Configuration Θ feedback voltage hre vc is very small and can be omitted. Therefore, hybrid ac equivalent circuit becomes. Thus , the comparison for hybrid versus re model for (a) common emitter and (b) common base configuration can be given, as shown in fig. 4.33 Figure 2.50 Common Base Configuration
9.
38 4A.273 © Copy
Right: Rai University ELECTRONICDESIGNTECHNOLOGY Thus, the re model can be converted to a hybrid model and vice- versa using the given relations rehie β= β=feh rehib = 1−≅−= αfbh Example.9: Given IE = 2.5mA, hfe =140, hoe =20 mS (mmho) and hob =0.5mS, determine: a) The common-emitter hybrid equivalent circuit. b)The common-base re model. Solution: Figure 2.51 Common Emitter Configuration (a) Ω=== 4.10 5.2 2626 mA mV I mV r E e Ω=Ω== kh reie 456.1)4.10)(140(β Ω=== k Sh r oe o 50 20 11 µ (b) Ω===≅ Ω= M Sh r r ob o e 2 5.0 11 1 4.10 µ α (a) Common-Emitter Configurations using hybrid model. (i) Fixed bias configuration For the fixed bias configuration of fig.2.53 a, the small signal ac equivalent model will appear as shown in Fig. 2.53b. Here, Zi : ZI = RB ||hie Zo : Zo =RC ||1/hoe Av : Using R=1/hoe ||RC ''00 RIhRIV bfe−=−= and ie i b h V I = with '0 R h V hV ie i fe−= so that ie oeCfe i V h hRh V V A )/1||(0 −== AI : Assuming that RB >>hie and 1/hoe ³10R, then Ib @Ii and Io = Ic = hfe Ii with fe i o h I I Ai ≅= Av : ie oeCfe h hRh Av )/1||( −= Ai: ie fe hR Rh Ai + = ' ' (ii) Unbypassed Emitter-Bias Configuration. For the CE unbypassed emitter-bias configuration of Fig. 2.54 the small-signal ac model will be the same as re - model , with bre replaced by hie and bIb by hfe Ib . The analysis will proceed in exactly the same manner. Zi : Zb @ hfe RE and ZI = RB ||Zb Zo : Zo =RC Av : Efe Cfe b Cfe v Rh Rh Z Rh A −≅−= and Av @ E C R R− AI : bB Bfe i ZR Rh A + = Example.10 For the network of Fig. 2.55, determine: (a) Zi . (b) Zo . (c) Av . (d) Ai .
10.
© Copy Right:
Rai University 4A.273 39 ELECTRONICDESIGNTECHNOLOGY Solution: Figure 2.55 (a) ZI = RB ||hie = 330kW||1.175 kW @ hie =1.171kW (b) Ω=== k VAh r oe o 50 /20 11 µ CC oe o RkkkR h Z ≅Ω=ΩΩ== 56.27.2||50|| 1 (c) 34.262 171.1 )50||7.2)(120()/1||( −= Ω ΩΩ −=−= k kk h hRh A ie oeCfe v (d) 120=≅ fei hA (iii) Voltage-divider Configuratioin For the voltage-divider bias configuration of Fig. 2.56 the resulting small-signal ac equivalent network will have the same appearance as Fig. 2.53b with RB replaced by R’=R1 ||R2 ZI : From Fig. 2.54 with RB =R’ ZI =R’|| hie Zo : From Fig. 2.54, Co RZ ≅ Fig. 2.56 or C i R Z AvA 1 −= (b) Emitter-Follower configuration For the emitter-follower of fig. 2.57a the small –signal ac model will match Fig. of re model bre = hie and b = hfe The resulting equations will therefore be quite similar. Zi : Zb @ hfe RE Zi =RB ||Zb Fig. 2.57a Emitter-follower configuration. Fig. 2.57b Defining Zo for the emitter-follower configura- tion. Zo : For Zo, the output network defined by the resulting equations will appear as shown in Fig. 4.32. Zo =RE || fe ie h h +1 or since 1+ fefe hh ≅ Zo = RE || fe ie h h
11.
40 4A.273 © Copy
Right: Rai University ELECTRONICDESIGNTECHNOLOGY Av : For the voltage gain the voltage-divider rule can be applied to Fig. 2.57a as follows )1/( )( feieE iE o hhR VR V ++ = since 1+hfe @hfe’ feieE E i o v hhR R V V A /+ ≅= Ai: bB Bfe i ZR Rh A + = or Ai = -Av E i R Z Fig. 2.57a Emitter-follower configuration. Fig. 2.57b Defining Zo for the emitter-follower configuration. (c) Common-Base Configuration using hybrid model Fig. 2.58a Common-base configuration Fig. 2.58b Substituting the approx., hybrid equivalent circuit into the ac equivalent network of fig. 2.58b
Download now