Electronics - Operational Amplifiers - Discussion
Discussion Forum : Operational Amplifiers - General Questions (Q.No. 17)
17.
If a noninverting amplifier has an RIN of 1000 ohms and an RFB of 2.5 kilohms, what is the RIN voltage when 1.42 mV is applied to the correct input?
Discussion:
16 comments Page 1 of 2.
ASHOK KUMAR.R said:
1 decade ago
According to the Virtual Ground concept if the inverting terminal is Grounded then the Rin will looks like parallel to that of the source.
So the voltage drop across the Rin is equal to the applied voltage.
So voltage across Rin is 1.42mA.
So the voltage drop across the Rin is equal to the applied voltage.
So voltage across Rin is 1.42mA.
Daks said:
1 decade ago
Vin = Vo((Rf/R1)+1)).
Vin = 1.42mv*3.5
Vin = 4.97mv.
The current passing throughout RF and R1.
RF+R1 = 3.5K.
I = Vout/RT.
I = 4.97mV/3.5k.
I = 1.42X10-6 amps.
Vr = I*R1.
Vr = 1.42x10-6 x 1k.
Vr = 1.42mv.
Vin = 1.42mv*3.5
Vin = 4.97mv.
The current passing throughout RF and R1.
RF+R1 = 3.5K.
I = Vout/RT.
I = 4.97mV/3.5k.
I = 1.42X10-6 amps.
Vr = I*R1.
Vr = 1.42x10-6 x 1k.
Vr = 1.42mv.
(1)
Satish kumar said:
8 years ago
Vo=Vin(1+Rf/Rin)).
Vo=1.42*10^3(1+2.5*10^3/100.0)
Vo=4.97mV.
The Voltage across Rin=Rin*Vo/Rin+Rf.
= 1.42mV.
Vo=1.42*10^3(1+2.5*10^3/100.0)
Vo=4.97mV.
The Voltage across Rin=Rin*Vo/Rin+Rf.
= 1.42mV.
Bhoopendra said:
1 decade ago
Negative terminal of op amp is at virtual ground therefore at this point the voltage will be equal to applied voltage at positive terminal.
Manisha khurana said:
9 years ago
This is not virtual ground situation. Virtual ground is the case when terminal is grounded directly but here there is feedback from output.
Mahesh said:
1 decade ago
Other end is grounded so due to virtual ground concept the voltage at non inverting pin will be zero so drop will be across 1kohm.
Ajinkya said:
9 years ago
As the circuit is non-inverting, it means there is no change at the o/p voltage. That means I/p voltage = o/p voltage.
Thank you.
Thank you.
Saifudheen said:
7 years ago
Vo=vin * (1+R2/R1)=1.42*3.5.
The voltage across R1 = Vo*(R1/(R1+R2)) = Vo/3.5 = 1.42mv.
The voltage across R1 = Vo*(R1/(R1+R2)) = Vo/3.5 = 1.42mv.
(1)
Vicky said:
1 decade ago
I think mahesh and bhoopendra is right. Thanks friends.
Naeem Khattak said:
8 years ago
@Daks.
Thanks for solving the question in detail.
Thanks for solving the question in detail.
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