Electrical Engineering - Circuit Theorems and Conversions - Discussion
Discussion Forum : Circuit Theorems and Conversions - General Questions (Q.No. 1)
1.
Find the Thevenin equivalent (VTH and RTH) between terminals A and B of the circuit given below.
4.16 V, 120 
41.6 V, 120
4.16 V, 70
41.67 V, 70
Discussion:
43 comments Page 2 of 5.
T.Ramachandran said:
1 decade ago
Vth = the voltage across the 120 Ohms. this is calculated by determining the current in the loop by applying KVL.
The KVL in the loop is,
100 - 68I - 100I - 120I = 0
=> 100 = 68I + 100I + 120I
=> I = 100/288
=> I = 0.347A
and,
Vth = 120 * I
Vth = 120 * 0.347 = 41.67V
To find Rth,
68 and 100 in series and this series combination come in parallel with 120 Ohms.
So,
Rth = (168*120/168+120)
Rth = 58.33 Ohms.
The KVL in the loop is,
100 - 68I - 100I - 120I = 0
=> 100 = 68I + 100I + 120I
=> I = 100/288
=> I = 0.347A
and,
Vth = 120 * I
Vth = 120 * 0.347 = 41.67V
To find Rth,
68 and 100 in series and this series combination come in parallel with 120 Ohms.
So,
Rth = (168*120/168+120)
Rth = 58.33 Ohms.
(1)
RAJIV SINGH said:
10 years ago
Using voltage dider rule(vth) = 100 * 120/(60 + 100 + 120) = 41.66.
And rth = (100 + 68)/(100 + 68 + 120) = 70.
And rth = (100 + 68)/(100 + 68 + 120) = 70.
(1)
Sharmila said:
10 years ago
168 ohms and 41.67v are correct.
(1)
Mvs said:
9 years ago
Yes, correct @Eee.
When calculating the Venin voltage is equal to open circuit voltage.
When calculating the Venin voltage is equal to open circuit voltage.
(1)
Thangam said:
1 decade ago
I need simple formula for solving these circuit analysis.
Prabha said:
1 decade ago
I can't understand.
Maheshwaran said:
1 decade ago
Vth = R3*(Vs/(R1+R2+R3))= 120*(100/(68+100+120)) = 41.67 V.
Rth = R3//(R1+R2) = (120*160) / (120 + 168)= 70 ohm.
Rth = R3//(R1+R2) = (120*160) / (120 + 168)= 70 ohm.
Khinya Ram Choudhary said:
1 decade ago
Let R = R1+R2;
Rth = R||R3;
According to Thevenin Theorem:
Rth = (168*120/(168+120)) = 70 Ohm.
Vth is Thevenin voltage Between A&B,
According to Voltage Divider Rule:
Vth = Vs*R3/ (R+R3).
= 41.67 V.
Rth = R||R3;
According to Thevenin Theorem:
Rth = (168*120/(168+120)) = 70 Ohm.
Vth is Thevenin voltage Between A&B,
According to Voltage Divider Rule:
Vth = Vs*R3/ (R+R3).
= 41.67 V.
Anshu said:
1 decade ago
When we have to find the venin voltage b/w two terminal then, firstly we have to remove the load resistance b/w these terminal. So why all are considering r3?
Naveen said:
1 decade ago
Rth = 168.
Vth = 100 V.
Vth = 100 V.
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