Lab #6
Follow the instruction and procedures in the Student Manual, unless specified differently
in this note.
Reading:
p.124 – 138 in SM
Ch. 2.15 – to end in AE
Lab #6
6-1 Use the following set-up for the differential amplifier shown below. (Wire +Vin the
same way as shown in the figure for –Vin, i.e. =Vin should also be connected to the
output of FG 2, common signal through 100 Ohm resistor). Estimate the common mode
gain and differential mode gain of the circuit. Use 3 Vp-p 100 Hz sine to measure Gcm.
Use .2 Vp-p 1 kHz for Gdm. Follow the instruction. What is the CMRR for A & B.
6-2 Follow the instruction. Note that there is no direct connection between 10 k
resistors and 0.1 uF capacitor in the circuit.
6-3 Skip
6-4 Follow the instruction. It won’t be easy to pull Ic down to 1 mA range. If you
measure around 6 mA with 20 MOhm, you are OK. Conduct simulation as described
below and compare the results between your exp. and sim.
FG1
Difference
Signal
BNC
Diff. amp.
v1in
vout
v2in
100 Ω
Chan 1 Chan 2
Scope
FG2
Common
Signal
BNC
6-4 Darlington / PSpice Simulation
Step 3: Running parametric simulations
Step 1: Drawing the circuit schematic
• Draw circuit above, parts need are:
2 Q2N3904 transistors
3 Resistors
2 Voltage supplies DC
3 connections to GrouND
BUBBLEs
• Use Ctrl-r to rotate and Ctrl-f to flip the parts
accordingly.
• Enter the parameter values for all known
parts and label the bubbles
Step 2: Setting up parametric simulations
•
•
•
•
•
Select the PARAMETER for the parametric
simulation
The value of this parameter will be a name
inside the curly brackets (i.e. {AbCdE})
In the part list search for PARAMETER and
place it on the schematic (see picture in next
column)
In the name field type the parameter name
without the curly brackets
For value type the DC Bias Point value
•
Open the “set up analysis” tab and select
PARAMETRIC
• Click on parametric and enter the
following parameters:
Sweep var. Type: Global parameter
Name: R
Sweep Type: Linear
Start Value: 500
End Value: 5k
Increment: 0.5k
• Click “OK”
• Select TRANSIENT
• Close the “set up analysis” tab
• Run the simulation
Step 4:Markers and Output file
•
Place the current or voltage markers
anywhere you need on the schematic
voltage/current will show in the probe
program
•
The probe program produces an output file
(>View>Output File) which contains all
relevant information about the circuit (i.e.
device parameters, Beta AC, Beta DC,
Power dissipation, etc.)