Hello there , first time poster .
I'm trying to find the Voutput of this circuit ( attachment ) but i think i am missing something .
Using the superposition principle i begin by grounding V2 to find the effect V1 has at Vo and then i ll do the same for V2 and add them to find the total output but im left with 4 equations and 5 variables system that i just cant solve .
Anyway these are the equations with V2 grounded :
Using KCL at the 4 nodes ( a , b , c , d ) :
a -> (v1-Va)/R1 = - (Vc - Va)/R2
b-> Vb/R1= (Vd - Vb)/R2
c-> (Vo-Vc)/R2 = (Vc- Va)/R2 + (Vc- Vd)/Rg
d-> (Vc-Vd)/Rg =Vd/R2 + (Vd - Vb)/R2
then we know that Va=Vb :
a -> (v1-Va)/R1 = - (Vc - Va)/R2
b-> Va/R1= (Vd - Va)/R2
c-> (Vo-Vc)/R2 = (Vc- Va)/R2 + (Vc- Vd)/Rg
d-> (Vc-Vd)/Rg =Vd/R2 + (Vd - Va)/R2
Thats the 4 equations/5 variables system and i just cant find an expression of Vo only dependant on V1
Some stuff i ve found : Vo = 2 ( Vc + Vd - Va )
(Vc-Vd)/Rg = - R2*V1/R1*Rg
So , is there something im missing ? (a current or voltage equation ? or some other method i could follow ?)
When i first saw the circuit i thought thats an opamp with both positive and negative feedback with Rg setting the amount of possitive feedback . Is this right in any way ?
Thanks for any tips/help/pointers beforehand and sorry for any grammatical errors i may have .
I'm trying to find the Voutput of this circuit ( attachment ) but i think i am missing something .
Using the superposition principle i begin by grounding V2 to find the effect V1 has at Vo and then i ll do the same for V2 and add them to find the total output but im left with 4 equations and 5 variables system that i just cant solve .
Anyway these are the equations with V2 grounded :
Using KCL at the 4 nodes ( a , b , c , d ) :
a -> (v1-Va)/R1 = - (Vc - Va)/R2
b-> Vb/R1= (Vd - Vb)/R2
c-> (Vo-Vc)/R2 = (Vc- Va)/R2 + (Vc- Vd)/Rg
d-> (Vc-Vd)/Rg =Vd/R2 + (Vd - Vb)/R2
then we know that Va=Vb :
a -> (v1-Va)/R1 = - (Vc - Va)/R2
b-> Va/R1= (Vd - Va)/R2
c-> (Vo-Vc)/R2 = (Vc- Va)/R2 + (Vc- Vd)/Rg
d-> (Vc-Vd)/Rg =Vd/R2 + (Vd - Va)/R2
Thats the 4 equations/5 variables system and i just cant find an expression of Vo only dependant on V1
Some stuff i ve found : Vo = 2 ( Vc + Vd - Va )
(Vc-Vd)/Rg = - R2*V1/R1*Rg
So , is there something im missing ? (a current or voltage equation ? or some other method i could follow ?)
When i first saw the circuit i thought thats an opamp with both positive and negative feedback with Rg setting the amount of possitive feedback . Is this right in any way ?
Thanks for any tips/help/pointers beforehand and sorry for any grammatical errors i may have .
Attachments
-
9 KB Views: 28