how can i get the difference between two voltage

[copoler]

for example,how can i get v1-v2,provided that both v1 and v2 are available.

 

[anggoro_yn]

If I'm not mistaken, when you connect one end of your circuit to V1 and the other end to V2 then you get V1-V2.

V1
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|
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----
| | R
| | Load
| |
----
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V2

Vrload = V1-V2

aaNg

 

[artem]

Use opamp to get 2 voltage difference . Or invert one of the voltage and sum them via resistors network .

 

[VVV]

Use an opamp, like in the picture.
If resistors are equal, you get Vout=V1-V2.

If R1=R4 and R2=R3, then the output will be Vout=G*(V1-V2), where G=R3/R1.

 

[seadolphine2000]

The subtractor circuit using OP-Amp is great but, for my knowledge....

Can't it be done directly with a voltmeter.??? Taking V1 with respect to V2.???

Please correct If I'm worng.

Thanks

 

[alvarorahul]

what you (seadolphine2000 ) is quite true , however if we want to use V-V2 in some other part of the circuit then that can't be done using a voltmeter can it??? in that case we will have to use some circuit such as the op-amp circuit given by VVV

in VVV's circuit if we put R1=R2=R3=R4=R we will get V0=V1-V2

 

[copoler]

Thanks VVV for your circuit.
Also,i guess there is a little mistake,if R1*R4=R2*R3,then Vo=R3/R1(V2-V1)

 

[xmli1976]

instrument operational amplifers can do it