Download presentation

Presentation is loading. Please wait.

Published byMagdalene Dixon Modified over 2 years ago

1
**Lecture 5 Source Transformation Thevenin Equivalent Circuit**

Norton Equivalent Circuit

2
**Circuit Techinques Ohm’s Law P=VI KCL, KVL Voltage/current divider**

Series/parallel resistance Mesh/Nodal Analysis Source Transformation Thevenin/Norton Equivalent Circuit Superposition Principle Maximum Power Transfer

3
**Source Transformation**

Show that iS=vS/R for any RL

4
**Thevenin Equivalent Circuit**

5
**Determine the Thevenin Voltage (VTh)**

If RL=∞ (load across a-b is removed), then Vab=VTH RTH does not play a role!

6
**3 Bit Digital to Analog Converter**

741 Op-Amp Chapter 5

7
Sample DAC Waveform DAC Output Digital Input

8
Applications Most modern audio signals are stored in digital form (e.g. MP3 and CDs) and in order to be heard through speakers they must be converted into an analog signal

9
**Thevenin Equivalent Circuit**

10
Determine VTH

11
**Methods of Finding RTH RTH=VTH/iSC**

If RL=0, the short circuit current from a to b (i.e. iab) should equal to isc=VTh/RTH. So RTH=VTh/isc If the network contains only independent sources: Deactivate a voltage source by replacing it with a short Deactivate a current source by replacing it with an open If the network contains dependent sources Apply a test source

12
**Calculate the Thevenin Resistance**

RTH

13
**If the network contains only independent sources**

RTH?

14
RTH

15
**Methods of Finding RTH RTH=VTH/iSC**

If RL=0, the short circuit current from a to b (i.e. iab) should equal to isc=VTh/RTH. So RTH=VTh/isc If the network contains only independent sources: Deactivate a voltage source by replacing it with a short Deactivate a current source by replacing it with an open If the network contains dependent sources Apply a test source

16
**Degenerated Common Emitter Amplifier (from last lecture)**

17
**What if we drive the base with a small signal?**

Vin, m=1 mV Vout, m=46 mV

18
**Mesh Analysis (Last Lecture)**

ne=2 essential nodes be=3 essential branches 3-(2-1)=2 equations

19
**Mesh Analysis (Last Lecture)**

1 2 Loop 1: clockwise Loop 2: counter-clockwise Clockwise around loop 1: +Vin-i1rπ-(i1+i2)RE=0 Counter-clockwise around loop 2: i2=gmi1rπ Vout =-i2RC

20
**Mesh Analysis (Details)**

21
**Determine RTH when a Dependent Source is Present**

IT

22
**Methods of Finding RTH RTH=VTH/iSC**

If RL=0, the short circuit current from a to b (i.e. iab) should equal to isc=VTh/RTH. So RTH=VTh/isc If the network contains only independent sources: Deactivate a voltage source by replacing it with a short Deactivate a current source by replacing it with an open If the network contains dependent sources Apply a test source

23
Another Way to Find RTH isc

24
**RTH Calculation iSC=10V/100 KOhms=0.1 mA VTH=10V/2=5V**

RTH=VTH/iSC=5V/0.1 mA=50 KOhms

25
**Norton Equivalent Circuit**

A Norton Equivalent circuit consists of Short-Circuit Current Norton Equivalent Resistance, which is equal to Thevenin Equivalent Resistance

26
**Getting A Norton Equivalent Circuit from Thevenin Equivalent Circuit**

RTH Thevenin Equivalent Circuit VTH Norton Equivalent Circuit IN=VTH/RTH RTH

27
**Derivation of Norton Equivalent Circuit**

RTH VTH IN=VTH/RTH RTH

28
**Extra Credit Assignment**

Derive

29
**More about the Extra Credit Assignment**

30
**Extra Slides on Thevenin**

31
Determine vab Show that VTH=vab

32
Determine iSC and RTH

33
Example 4.10 Determine the Thevenin Equivalent Voltage

34
Example 4.10 Determine the short circuit current Determine RTH

35
**Slides on Source Transformation**

36
RTH

37
**Application Determine whether the 6V source is**

absorbing or delivering the power.

38
**Step-by-step simplification**

39
Redundant Resistor (1) Prove that the left circuit and the right circuit are equivalent for any load resistor.

40
Redundant Resistor (2) Prove that the left circuit and the right circuit are equivalent for any load resistor.

41
Example 4.9

42
Simplified Circuit

Similar presentations

OK

1 Summary of Circuits Theory. 2 Voltage and Current Sources Ideal Voltage Source It provides an output voltage v s which is independent of the current.

1 Summary of Circuits Theory. 2 Voltage and Current Sources Ideal Voltage Source It provides an output voltage v s which is independent of the current.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on mars rover Ppt on rational numbers Ppt on hplc method development and validation Powerpoint ppt on communication skills Jit ppt on manufacturing engineer Ppt on maths tricks and tips Ppt on polynomials download google Climate change for kids ppt on batteries Free download ppt on resources and development for class 10 Ppt on uttar pradesh tourism