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.
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.
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
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.
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.
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.
Ami said:
1 decade ago
Gain is indirectly/inversly proportional to rf/r1 as gain increse result decrease.
Assimo said:
2 years ago
@Khizer.
If the impedance decreases, then it increases but in negative.
If the impedance decreases, then it increases but in negative.
Lakshmi said:
10 years ago
@Subbu.
How do say R1 is input resistance?
How do say R1 is input resistance?
Ooredoo said:
4 years ago
Explain about input impedance, please.
Srinivas said:
1 decade ago
It is invert op-amp so gain= -Rf/R1.
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