Thevenin Equivalent for a circuit containing a dependent source
6
ECE 201 Circuit Theory I 1 Thevenin Equivalent for a circuit containing a dependent source V 5 V R1 2kOhm V2 3 V/V I1 20 A/A R2 25 Ohm a b
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Thevenin Equivalent for a circuit containing a dependent source. Determine the Thevenin voltage V Th. + V Th -. I. 20 I. Determine the Thevenin resistance R Th. - PowerPoint PPT Presentation
Transcript of Thevenin Equivalent for a circuit containing a dependent source
ECE 201 Circuit Theory I 1
Thevenin Equivalent for a circuit containing a dependent source
V5 V
R1
2kOhm
V23 V/V
I120 A/A
R225 Ohm
a
b
ECE 201 Circuit Theory I 2
Determine the Thevenin voltage VTh
Th
Th
Th
V = -20I(25) = -500I
5 -3V5 -3V 5 -3(-500I)I = = =
2000 2000 20005 1
I = =500 100
V = -500I = -5Volts
+
VTh
-
I
20 I
V5 V
R1
2kOhm
V23 V/V
I120 A/A
R225 Ohm
a
b
ECE 201 Circuit Theory I 3
Determine the Thevenin resistance RTh
V5 V
R1
2kOhm
V23 V/V
I120 A/A
R225 Ohm
a
b
De-activate the independent voltage source and excite the circuit from the a-b terminals with either a voltage or current source. Here, use a voltage source – then we will know the dependent voltage and dependent current.
ECE 201 Circuit Theory I 4
Thevenin Resistance (continued)
R1
2kOhm
V23 V/V
I120 A/A
R225 Ohm
a
b
VT12 V
IT
Apply voltage VT and determine the current IT.
The Thevenin Resistance will be RTh = VT / IT.
ECE 201 Circuit Theory I 5
Thevenin Resistance (continued)
R1
2kOhm
V23 V/V
I120 A/A
R225 Ohm
a
b
VT12 V
ITI
20 I
TT
T
T TT
TTh
T
VI = +20I
253V
I = -2000V 3V
I = +20 -25 2000
I 1 6 1= - = R =100Ω
V 25 200 100
ECE 201 Circuit Theory I 6
The Thevenin Equivalent Circuit
Vth5 V
Rth
100 Ohm a
b
