Practice 4. Effects of increasing and decreasing R2

In this practice, the effects of changing the value of R2 will be examined. The practice includes 2 parts:

    a) increase the value of R2.

    b) decrease the value of R2.

 Following is the procedure for the practice, as well as analysis of the effects of changing the value of R2.

 a)      Increase the value of R2

 Procedure:

      1.       Click “Continue” to start the simulation

2.       After a while (e.g. when the curves are reaching the 5th grid), pull up the scaler in the scrollbar next to “R2” to increase the value of R2.

3.       Observe how each of the 5 curves (except the curve for ui) changes.

 


 

Analysis:

 

R2: increase =>

UB = Ucc*R2/(R1+R2): increase

            URE = UB - 0.7: increase

UC = Ucc - IC*RC: decrease

[because IC = IRE = URE/RE: increase]

uo = -40*IC0*RC*ui1: increase

[because IC = IRE = URE/RE: decrease]

Uout = UC + uo: decrease

[because although uo increases at the same time UC decreases, the decreased amount of UC is much larger than the increased amount of uo]

b)      Decrease the value of R2

Procedure:

     1.       Click “Continue” to start the simulation

     2.       After a while (e.g. when the curves are reaching the 5th grid), pull down the scaler in the scrollbar next to “R2” to decrease the value of R2.

     3.       Observe how each of the 5 curves (except the curve for ui) changes.

 Analysis:

 R2: decrease =>

UB: decrease

            URE: decrease

UC: increase

uo: decrease

Uout: increase