Electronic Devices - Operational Amplifiers - Discussion
Discussion Forum : Operational Amplifiers - General Questions (Q.No. 2)
2.
Refer to this figure. If the value of R1 decreases, the voltage gain will ________ and the input impedance will ________.
Discussion:
12 comments Page 1 of 2.
Reena said:
1 decade ago
V0/Vin=-(Rf/R1)
Gain inversely prop to R1
therefore: R1 decrease gain increase
input impedance decrease
Gain inversely prop to R1
therefore: R1 decrease gain increase
input impedance decrease
Shri ram said:
1 decade ago
Gain=-(Rf/Ri)
here u can c this -ve sign. If a -ve value increases means it is actually decreasing.
here u can c this -ve sign. If a -ve value increases means it is actually decreasing.
Ami said:
1 decade ago
Gain is indirectly/inversly proportional to rf/r1 as gain increse result decrease.
Srinivas said:
1 decade ago
It is invert op-amp so gain= -Rf/R1.
Rishikesh said:
1 decade ago
What about Impedance?
Subbu said:
1 decade ago
R1 only input impedance.
If R1 decreases then automatically input impedance decrease.
If R1 decreases then automatically input impedance decrease.
Khizer said:
1 decade ago
Here answer is wrong. Because of minus sign. If R1 decreases then the answer will be big but in negative.
Aravind said:
1 decade ago
@Khizer:
Actually the negative sign indicates that the output will be shifted by 180 degree. So no need to consider about that negative sign.
Actually the negative sign indicates that the output will be shifted by 180 degree. So no need to consider about that negative sign.
Lakshmi said:
10 years ago
@Subbu.
How do say R1 is input resistance?
How do say R1 is input resistance?
Abdul Qayum said:
5 years ago
Thanks @Arvind.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers