Electronic Devices - Operational Amplifiers - Discussion
Discussion Forum : Operational Amplifiers - General Questions (Q.No. 7)
7.
Refer to the given figure. The input impedance of this circuit is
500 k
.
.10 k.
.50 k.
.5 k.
.Discussion:
8 comments Page 1 of 1.
Karthi said:
6 years ago
Please explain briefly.
Snehil said:
8 years ago
The (-) terminal of OPamp is a virtual ground.
Also the input impedance of an system = Vin/Iin.
Assuming Iin current to flow through the 50K resistor;
Applying KVL: Vin-50K(Iin)=0(virtual gnd).
Therefore, Vin/Iin=50K.
Also the input impedance of an system = Vin/Iin.
Assuming Iin current to flow through the 50K resistor;
Applying KVL: Vin-50K(Iin)=0(virtual gnd).
Therefore, Vin/Iin=50K.
(1)
Luchie said:
8 years ago
We know that in an inverting amplifier Zin=Ri.
Frido tarigan said:
8 years ago
Thanks for explaining it.
Haftu hiluf said:
9 years ago
Thank you for posting this.
These questions are quit conceptual for young engineer.
These questions are quit conceptual for young engineer.
Shubham said:
1 decade ago
Feedback resistor=500/ (1-gain) will come in parallel with 50k. So that o/p must be 50k parallel with feedback resistor.
Xyz said:
1 decade ago
But shouldn't the feedback resistor be added in series after using millers law?
Navneet said:
1 decade ago
Impedance = ri+jxi.
ri=50k and xi=0. So by above equation.
ri=50k and xi=0. So by above equation.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers