Electronic Devices - Op-Amp Applications - Discussion
Discussion Forum : Op-Amp Applications - General Questions (Q.No. 4)
4.
Determine the output voltage when V1 = –V2 = 1 V.
Discussion:
28 comments Page 1 of 3.
Mallik said:
1 decade ago
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
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
Dhanabal said:
1 decade ago
/* 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.
Vout = (v1-v2) * (-(rf/r1)).
= (1-(-1))*(-(100/100)).
= -2*1.
= -2.
Murad said:
1 decade ago
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.
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.
(1)
Kiran Borude said:
10 years ago
Opamp have one positive terminal & one negative terminal. That's why it is called one terminal is inverting & 2nd is non inverting.
ALI said:
8 years ago
(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.
The resulting output voltage is seen to be the difference of the two input voltage.
(1)
Rakesh said:
8 years ago
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.
Vo=-V1+(1/2)(2)V2.
Vo=-V1+V2,
Vo=-1+(-1) because -V2=1 => V2=-1,
Vo=-2 Volts.
Raj said:
1 decade ago
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
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
Shrestha said:
6 years ago
According to the differential amplifier fromula:
Vout = (R2/R1)*(V2-V1).
= (20/20)*(-1-1).
= 1*-2 = -2.
Vout = (R2/R1)*(V2-V1).
= (20/20)*(-1-1).
= 1*-2 = -2.
(2)
Vaibhav said:
6 years ago
Simple and easy the circuit shown acts as a difference amplifier and output voltage is given by vo =( v2-v1)x(Rf/R1).
(5)
SAUMIL said:
1 decade ago
Vo = (-RF/R1)V1 + (1+(RF/R1))V2'
= -1 + (1+1)(20*V1/40)
= -2 (ACCORDING TO ME..)
= -1 + (1+1)(20*V1/40)
= -2 (ACCORDING TO ME..)
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