need help on circuit problems.

[Omegachi]

i am trying to do my circuit analysis hw, but i don't seem to understand it. I have other hw to do, and it is already so late. here are the problems, please help.

link

i know that to find the network functions, it is to find the Vout/Vin. but the analysis part is just so confusing. please give me some pointers.

 

[Omegachi]

bump

 

[her209]

V=IR

 

[OS]

Originally posted by: Omegachi
i am trying to do my circuit analysis hw, but i don't seem to understand it. I have other hw to do, and it is already so late. here are the problems, please help.

link

i know that to find the network functions, it is to find the Vout/Vin. but the analysis part is just so confusing. please give me some pointers.

Make node equations for everything and move Vi,Vo to the side that you want.

Sorry, the line I had here wasn't really relevant.

 

[OS]

the first one is pretty simple, you want me to find the transfer function for you?

 

[AznMaverick]

Originally posted by: OS
the first one is pretty simple, you want me to find the transfer function for you?

i'm, too, am in the class. sure! just to help us out with the basic process and steps. i am really REALLY lost in circuits class, direct result of a crappy professor and book, the best help this semester are friends that actually get this stuff.

 

[OS]

pic

s and jw are used interchangeably

 

[pillage2001]

3 op amps in series?? Your lecturer is crazy

LOL

 

[OS]

Originally posted by: pillage2001
3 op amps in series?? Your lecturer is crazy

LOL

I've seen worse. Some of my lab problems need 5 opamps.

 

[AznMaverick]

Originally posted by: OS
pic

s and jw are used interchangeably

THANK YOU! your help is very appreciated!

 

[OS]

Originally posted by: AznMaverick
THANK YOU! your help is very appreciated!

sure thing. hope that's what you're looking for and that it makes sense.

 

[Ready]

For the 2nd problem I can give you a few pointers.
Because V- and Vout are connect, meaning it feeds back,
V+ and V- will always set at the same voltage so you can write the equation

V+ = V-

The 3rd question, no feedback, just write quite a few node equations ^^.
5 nodes I count 5 equations u need. But to make ur job easier

1ohm resistor in parallel with a 1F capacitor has an impedence of 1/(1+sc) or 1/(1+jcw)

The first equation taken at the input of the first opamp would be something like
[V+1 - Vin] + [(V+1 - Vout1)/(1/(1+sc))] + [(V+1 - Vout3)/.5] = 0


The 2nd equation take at the output of the first opamp would be something like
[(Vout1 - V+1)/(1/(1+sc))] + [Vout1 - V+2] = 0

The 3rd equation taken at the input of the 2nd opamp would be something like
[V+2 - Vout1] + [V+2 - Vout2] = 0

The 4th equation at the output of 2nd opamp
[Vout2 - V+2] + [(Vout2 - V+3)/.5] = 0

Equation 5 at the input of the 3rd opamp
[(V+3 - Vout2)/.5)] + [(V+3 - Vout3)/(1/sc)] = 0

 

[Omegachi]

thanks guys.