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

Click For Summary

Discussion Overview

The discussion revolves around the accuracy of a simulation of an operational amplifier (op amp) circuit using Multisim, comparing analytical results with simulated outcomes. Participants analyze current values derived from both methods and seek clarification on discrepancies.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents analytical results for the op amp circuit, detailing calculated currents (ia, ib, ic, ig, is) and component values.
  • Another participant requests the equations used to derive the results, indicating a need for clarity on the calculations.
  • A subsequent post provides the equations and calculations, showing step-by-step derivations for the currents based on voltage values.
  • Discrepancies are noted between the simulated current (Is) and the analytically calculated current, prompting questions about the simulation's accuracy.
  • One participant expresses satisfaction after resolving their confusion, suggesting a potential resolution to their initial query.

Areas of Agreement / Disagreement

Participants do not reach a consensus regarding the accuracy of the simulation, as discrepancies between analytical and simulated results remain a point of contention.

Contextual Notes

Limitations include potential assumptions in the circuit model, dependence on the accuracy of the simulation software, and the need for clarity on the definitions of voltage and current in the context of the op amp circuit.

Saeed.z
Messages
28
Reaction score
1
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 : )
 
Last edited by a moderator:
Physics news on Phys.org
Please show your equations for the results you got.
 
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
 
Last edited by a moderator:
=> 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
 
Last edited:
any help ? thanks
 
i got it ! thanks :)
 

Similar threads

Understanding Op-Amp Simulation in Multisim
  • · Replies 16 ·
Replies
16
Views
10K
Engineering Analyzing a Circuit with an Op-Amp
  • · Replies 2 ·
Replies
2
Views
2K
Engineering Op amp in circuit: find load current
  • · Replies 5 ·
Replies
5
Views
4K
Engineering Electronic circuit with Op-Amp, Switch and Diodes
  • · Replies 39 ·
2
Replies
39
Views
7K
Engineering Understanding Op-Amp Circuits: Simple Circuit Help & Calculation Tips
  • · Replies 8 ·
Replies
8
Views
4K
Engineering How Does Setting Rx to 60k Affect the Output Voltage in an Ideal Op Amp Circuit?
  • · Replies 11 ·
Replies
11
Views
20K