Discussion :: OpAmp Applications  General Questions (Q.No.4)
4.  Determine the output voltage when V_{1} = –V_{2} = 1 V.


Answer: Option B Explanation: No answer description available for this question.

Saumil said: (Feb 9, 2011)  
Vo = (RF/R1)V1 + (1+(RF/R1))V2' = 1 + (1+1)(20*V1/40) = 2 (ACCORDING TO ME..) 
Sumit said: (Nov 4, 2011)  
v0=(rf/ri)(v1v2) 
Shri said: (Nov 30, 2011)  
v0=(1+rf/ri)*v1+v2 ......v2=0 
Bhavik Desai said: (Feb 11, 2012)  
Vo = (RF/R1)V1 + (1+(RF/R1))V2' = 1 + (1+1)(20*V2/40) = 2 (ACCORDING TO ME..) 
Ananth said: (Feb 15, 2012)  
Simulation result says 2v. 
Mallik said: (Mar 26, 2012)  
Answer is 2v.. write the equations for the circuit using KCL... let say both the terminals of opamp are at common voltage Vb. now equation for first combination containing V1: [{(V1Vb)/100k}+{(VoVb)/100k}]=0. => V12Vb=Vo  (1) now equation for second combination containing V2: [(V2Vb)/20k] = [(Vb0)/20k] => Vb=V2/2  (2) from 1 & 2 Vo= V1V2; V0=V2V1; Vo= 11 =2v 
Murad said: (Apr 25, 2012)  
By using superposition principle: Vo'=(rf/r1)V1=1V Vi+= 1(20/40)=0.5V Vo''=(1+rf/r1)Vi+=2*(.5)=1 Vo=Vo'+Vo''=11=2V So the answer should be B. 
Raj said: (Jun 3, 2012)  
Vo'=(rf/r1)V1=1V Vi+= 1(20/40)=0.5V Vo''=(1+rf/r1)Vi+=2*(.5)=1 Vo=Vo'+Vo''=11=2V So the answer should be B.correct 
Savitri said: (Oct 9, 2012)  
Vo=rf/r1(v2v1). Vo=100k/100k(11)=2. 
Shakthivel said: (Jul 5, 2013)  
Vo = RF(V2V1)/R1. Vo = (11)100k/100k Vo = 2. 
Dhanabal said: (Jul 20, 2013)  
/* The above example v(inverting terminal) get more voltage than +v(non inverting) terminal*/ Vout = (v1v2) * ((rf/r1)). = (1(1))*((100/100)). = 2*1. = 2. 
Neetu Khadaria said: (Feb 24, 2014)  
Since its a circuit of subtractor whose o/p voltage is = v1v2= 2*v2 = 2*1 = 2. 
Youmna said: (Apr 25, 2014)  
R1 = 100K. R2 = 100K. Vo = R2/R1(V2V1). Vo = 100K/100K(11). Vo = 1(2). Vo = 2 Answer. 
Atul Raghav said: (Nov 28, 2014)  
Vo = (100k/100k)*1+(1+100k/100k)*{(1)*(20k/(20k+20k))}. = 1*1+2*(1)/2. = 11. = 2 Answer. 
Punam said: (Jan 28, 2015)  
Vo = (Rf/R1)(V1V2). 
Miss said: (Apr 10, 2015)  
Vo = Rf/R1*V1V2. = 100/100*1(1) V. = 2 V. 
Bayan said: (Oct 29, 2015)  
Why v2 negative? 
Kiran Borude said: (Jan 29, 2016)  
Opamp have one positive terminal & one negative terminal. That's why it is called one terminal is inverting & 2nd is non inverting. 
Shawn said: (Feb 19, 2016)  
I think the answer should be 0 V. Because the is not powered. So no amplification. 
Surya said: (Feb 28, 2017)  
It is diff amplifier Vo = (v2v1) = (11) =2. 
Sugin V said: (May 2, 2017)  
Here, V2/2 (1+Rf/Rs) + V1 (Rf/Rs). 
Rakesh said: (Oct 7, 2017)  
Vo=(100/100)V1+(20/(20+20))((100+100)/100)V2. Vo=V1+(1/2)(2)V2. Vo=V1+V2, Vo=1+(1) because V2=1 => V2=1, Vo=2 Volts. 
Ali said: (Nov 2, 2017)  
(20/20+20)(100+100/100)*V1(100/100)V2 = V1V2. The resulting output voltage is seen to be the difference of the two input voltage. 
David Khasu said: (Aug 4, 2018)  
Here, we can use {Rf÷R1}*(v1v2). 
Avi said: (Mar 18, 2019)  
[R3/(R1+R3][(R2+R4)/R2][V1][V2 (R4/R2)] is the formula. So it is 0V. 
Shrestha said: (Jun 3, 2019)  
According to the differential amplifier fromula: Vout = (R2/R1)*(V2V1). = (20/20)*(11). = 1*2 = 2. 
Praveen said: (Jun 21, 2019)  
Vo = (RF/R1)V1 + (1+(RF/R1))V2'. = 1 + (1+1)(20*V1/40), = 2. 
Vaibhav said: (Oct 7, 2019)  
Simple and easy the circuit shown acts as a difference amplifier and output voltage is given by vo =( v2v1)x(Rf/R1). 
Post your comments here:
Name *:
Email : (optional)
» Your comments will be displayed only after manual approval.