# Electronic Devices - Op-Amp Applications - Discussion

### Discussion :: Op-Amp Applications - General Questions (Q.No.4)

4.

Determine the output voltage when V1 = –V2 = 1 V. [A]. 0 V [B]. –2 V [C]. 1 V [D]. 2 V

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)(v1-v2)

 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 op-amp are at common voltage Vb. now equation for first combination containing V1: [{(V1-Vb)/100k}+{(Vo-Vb)/100k}]=0. => V1-2Vb=-Vo --------- (1) now equation for second combination containing V2: [(V2-Vb)/20k] = [(Vb-0)/20k] => Vb=V2/2 ---------- (2) from 1 & 2 -Vo= V1-V2; V0=V2-V1; Vo= -1-1 =-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''=-1-1=-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''=-1-1=-2V So the answer should be B.correct

 Savitri said: (Oct 9, 2012) Vo=rf/r1(v2-v1). Vo=100k/100k(-1-1)=-2.

 Shakthivel said: (Jul 5, 2013) Vo = RF(V2-V1)/R1. Vo = (-1-1)100k/100k Vo = -2.

 Dhanabal said: (Jul 20, 2013) /* The above example -v(inverting terminal) get more voltage than +v(non inverting) terminal*/ Vout = (v1-v2) * (-(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 = v1-v2= -2*v2 = -2*1 = -2.

 Youmna said: (Apr 25, 2014) R1 = 100K. R2 = 100K. Vo = R2/R1(V2-V1). Vo = 100K/100K(-1-1). 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. = -1-1. = -2 Answer.

 Punam said: (Jan 28, 2015) Vo = -(Rf/R1)(V1-V2).

 Miss said: (Apr 10, 2015) Vo = -Rf/R1*V1-V2. = -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 = (v2-v1) = (-1-1) =-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 = V1-V2. 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}*(v1-v2).

 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)*(V2-V1). = (20/20)*(-1-1). = 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 =( v2-v1)x(Rf/R1).