Practice 3. Effects of increasing and decreasing R1 

In this practice, the effects of changing the value of R1 will be examined. The practice includes 2 parts:

    a) increase the value of R1.

    b) decrease the value of R1.

 Following is the procedure for the practice, as well as analysis of the effects of changing the value of R1.

 a)      Increase the value of R1

 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 “R1” to increase the value of R1.

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


 

Analysis:

 R1: increase =>

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

            URE = UB - 0.7: decrease

UC = Ucc - IC*RC: increase

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

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

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

Uout = UC + uo: increase

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

 b)      Decrease the value of R1

 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 “R1” to decrease the value of R1.

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

 Analysis:

R1: decrease =>

UB: increase

            URE: increase

UC: decrease

uo: increase

Uout: decrease