Engineering Is the Simulation Accurate? Analyzing an Op Amp Circuit with Multisim

[Saeed.z]

hi everyone ,

i solved a textbook question which says :

http://img268.imageshack.us/img268/8994/img1379sa.jpg

http://img685.imageshack.us/img685/3228/img1380z.jpg

and found analytically : ia = -470 uA, ib = 770 uA , ic = 22 uA, ig= 322 uA, is = 64.5 uA

Ra= 1kohms, Rb=2kohms, Rc = 1.5 kohms, Rf= 210 kohms , Vo = 14.5 v

and i simulate it by using multisim as shown below :

http://img32.imageshack.us/img32/8847/simue.png

the current (Is) looks different ! is there something wrong with simulation ? thanks : )

 

[rude man]

Please show your equations for the results you got.

 

[Saeed.z]

ok ^^

Here is my solution :

http://img526.imageshack.us/img526/3480/ee1c.jpg

http://img444.imageshack.us/img444/1305/ee2f.jpg

hope it's clear :) thanks

 

[Saeed.z]

=> Vn = 29/30 v and Vo = 14.5 v

=> I s = ( Vn - 0 ) / 15k = 64.44 uA

I a = ( Va - Vp ) / 1k = -466.67 uA

I b = (Vb - Vp ) / 2k = 766.67 uA

I c = ( Vc - Vp ) / 1.5k = 22.2 uA

I g = ( Vp - 0 ) / 3k = 322.2 uA

 

[Saeed.z]

any help ? thanks

 

[Saeed.z]

i got it ! thanks :)