[The following is worksheet for PSpice simulation used for the Computer Lab Recitation.  Students, Electrical and Computer Engineering juniors, follow the instruction given below to do the PSpice Schematics and simulation and fill out this spreadsheet which is graded by the TA at the end of 1.5-2 hour recitation session.  This is self contained instruction, the textbook is not necessary for doing it.  If any part of this workseet is deficient, then try this Word document.]

Problems for this week (Textbook: Microelectronic Circuits by Sedra/Smith]:

1. Problem 4.35(Page # 336)
2. Exercise 4.20(page # 253)
3. Problem 4.64(Page # 340)

INSTRUCTIONS:

Problem 4.35:
For the circuits shown in Fig P4.35 (a) and (e), find the values for the labeled node voltages and branch currents. Assume b to be very high.
Part (a):
PARTS USED: Q2N3904, R, VDC, GND_EARTH
 

Step 1: Using Pspice schematics, build the figure given below.

Step 2: Choose the transistor and go to
EDIT?MODEL?Edit Instance Model Text.
Change Bf=10000(very high value)
 Step 3: Simulate the circuit and measure the voltages V1 and V2 directly from the schematics.
 Step 4: To view the voltages click the voltage display button V on the toolbar and verify with your hand calculated value.
 

 Step 1: Using Pspice schematics, build the figure given below.
Step 2: Choose the transistor and go to
EDIT ==> MODEL ==> Edit Instance Model Text.
Change Bf=10000(very high value)
Step3: Simulate the circuit and note down the measured values.
NOTE: Your measured values will be slightly away from the hand-calculated values.

EXERCISE 4.20:
 Use the circuit given below to find the voltages and current.

HAND CALCULATION:
This problem has been solved in the lecture, you can verify with that.

PSICE PROCEDURE:
    Step 1: Using schematics draw the circuit given below.

Step 2:Click or choose transistor Q3.Goto

  EDIT ==> MODEL ==> Edit Instance Model text

Change Bf = 100. (Bf is the spice parameter for b)

 Step 3: Simulate  the circuit and note down the marked voltages VE1, VE2, VE3 and VC2.Verify the results with your hand calculated values.
 Step4: Note the currents through all branches. (You can use the Example4.8 (page #251 as reference for this problem)

Problem 4.64:
 Assume ? is very large and find the collector current IC, vo1/vi,and vo2/vi.Use figure p4.64.

PROCEDURE:
 Step 1: Using PSPICE schematics draw the given circuit.

Step 2:Goto Analysis?Setup?ACSweep.
Step 3: Simulate the circuit.
Step 4:Measure the current from the schematics using Current markers.
Step 5: Plot vo1/vi and vo2/vi and check the output with your hand-calculated values.
Step 6: Go to Analysis?Examine output.
A text window will open. Keep scrolling down till find BIPOLAR JUNCTION TRANSITORS.
Under that you will various parameters. You can check your GM, IC, and IB etc. from the output file.
NOTE: Your output file also gives the node voltages and currents.

The currents for the active mode and saturation mode are implemented in SPICE as the following:
 

[1]. Normal Active Mode:

I_C = Is (e^qV_BE^/kT + 1/ß_R) + [V_BE - (1 + 1/ß_R)V_BC] GMIN

I_B = Is [1/ß_F(e^qV_BE^/kT - 1) - 1/ß_R] + (V_BE/ß_F + V_BC/ß_R) GMIN
 
 

[2]. Saturation Mode:

I_C = Is [(e^qV_BE^/kT - e^qV_BC^/kT) - 1/ß_R(e^qV_BC^/kT - 1)] + [V_BE - (1 + 1/ß_R)V_BC] GMIN

I_B = Is [1/ß_F(e^qV_BE^/kT - 1) + 1/ß_R(e^qV_BC^/kT -1)] + (V_BE/ß_F + V_BC/ß_R) GMIN
 
 

Where:

Is --- Saturation current, the default value is 10^-16A.

ß_F --- Ideal maxmum forword current gain, the default value is 100.

ß_R --- Ideal maxmum reverse current gain, the default value is 1.

GMIN --- a samll conductance, the default value is 10^-12 mho.