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A. SCHEMATIC: Submit your PSpice schematic clearly showing all values for DC

voltage, DC current and DC Power for each element. All resistor values must clearly be

shown on the schematic.

B. SIMULATED DC BIAS: What are the simulated DC bias parameters, ICQ, VCEO, VBEQ

and transistor Power Dissipation, PD, transistor? Submit a table comparing your hand-

calculated values to the simulated values for Ico, VCEO, VREQ, and PD, transistor.

C. SIMULATED POWER SUPPLY BIAS: What is the total current delivered from the

supply, Irs? Did you achieve the specification for maximum current?

D. SIMULATED CURRENT SWING: Simulate your design in PSpice using a 1kHz

sinusoidal input, use a voltage source with a 1K source resistor as shown above. Place a

current probe on the wire leading into your circuit (on the left side of the capacitor). What

is the largest peak-to-peak swing in the output current, i, through the 64 ohm load

resistance? To find the maximum swing, you should slowly increase the source amplitude

until the output current waveform begins to clip at the top or the bottom. Unless you have

a design optimized for maximum symmetrical swing, it's most likely that the clipping will

not be symmetrical. In other words, the point of clipping in the positive peak current will

be different from the negative peak current. Submit a plot showing it with clipping using

a B-200. When clipping occurs, chose the smaller of the two values and double this

value, this is the peak-to-peak swing in the output current, IL. Clearly report this peak-to-

peak swing in the output current, L. Did your design achieve the 100mA peak-to-peak

swing?

E. SIMULATED EFFICIENCY: Using the peak swing in load current, it (just below

clipping), and load resistance, 64 ohms, calculate the simulated power conversion

efficiency, n? You will need the total power supply current, Ips, from your simulation.

Show all your calculations using data recorded from your simulated plots. Compare the

hand-calculated value to the simulated value.

F. SIMULATED SMALL SIGNAL OPERATION: Using PSpice, reduce the input source

amplitude so that it is should be small enough to operate your transistor in the small signal

region. Verify that the peak AC voltage across the Base-Emitter (B-E) junction, Vie, is less

than 2.6mV peak (<<26mV). In OrCAD, you can verify the voltage using the

"Differential Voltage Probe" measurement or just take the difference between two voltage

probes placed at the base and the emitter. If vie is greater than 2.6mV, decrease the source

amplitude until the B-E voltage is in the small signal range. Record the amplitude value

of the source voltage for small signal operation. Submit a plot showing of the for B-200./nG. SIMULATED GAIN: Using the input source with amplitude set to the value found in part

(F), what is the small signal gain, A₁ =, at ß- 200? Submit two plots showing is and

it under small signal conditions using a B-200. Edit the transistor model and change the

value for 3 to 100 and then to 300, record the small signal gain for each condition. What

is the variation in the current gain, A₁ =, when ß is varied over the range from 100 to

EE3124

Project #1 -Fall 2023

Rev 0.0

Class A Power Amplifier Design

300? Submit a table showing current gain, A₁ = for B-100, 200 and 300. What is

the % variation in your gain across this range in B (relative to B-200, percent variation is

calculated using (simulated-target x100%))?

H. SIMULATED INPUT RESISTANCE: Using the source amplitude found in part (F), what

is the simulated input resistance, Rin, to your amplifier? Using current and voltage test

probes at the amplifier input to calculate the input resistance using PSpice by placing

cursors at the peak of each sinusoidal waveform and dividing the voltage result by the

current. Note that the placement of V/I probes on the schematic in circuit areas where

there is DC voltage and/or DC current will result in a DC offset in the simulated

measurements, if so, either move the probe or subtract the DC offset from the results.

Submit two plots showing the voltage and current waveforms used to calculate Rin

having ß-200. Submit a table comparing your hand calculation and PSpice value for

Rin. Submit a table showing PSpice values for Rin with ß-100, 200 and 300.

I. SIMULATED OUTPUT RESISTANCE: What is the output resistance, Rout, to your

amplifier? Replace the 64 ohm load with a voltage source at the output of your amplifier

(leave the coupling capacitor between the source and the circuit). Remove the input

voltage source and replace with a short (vi-0). Using current and voltage test probes at

the amplifier output, calculate the output resistance, Rout, using PSpice by placing

cursors at the peak of each waveform and dividing the voltage result by the current. The

voltage source should have a low amplitude to maintain a small signal condition. Submit

the PSpice schematic of your test circuit. Submit a plot showing vo and io on two

separate graphs for ß-200. Submit a table showing Rout for ß- 100, 200 and 300.

J. SIMULATION USING STANDARD RESISTOR VALUES: Using your PSPICE design,

substitute standard resistors into your model by rounding up or down to the nearest

values. The standard resistor values are listed in Appendix A noting there are two

columns, one for 1/2 watt and one column for 3W. Match the resistance and associated

power requirements to your design. SUBMIT the schematic with Standard Resistors.

Using B-200, simulate the peak-peak current swing, small signal current gains and input

resistance. Submit a table, comparing PSpice results for Vcc, Ico, VCEQ, PD, transistor with

original resistors and the standard value resistors./nK. Submit a plot showing it with clipping at both the positive and negative peaks using a B

-200. Submit plots of is and it under small signal conditions, calculate A₁. Submit plots

of fin and vin under small signal conditions, calculate R. Submit a table comparing the

simulated peak swing, the simulated small signal gain and input resistance for your

original design and the design with standard resistors.

L. COMPONENT BILL OF MATERIALS (BOM) FOR LAB EXPERIMENT #3: Create

the BOM, with standard resistor values (ohms), the quantities for each type of resistor and

the required power spec (½ watt or 3 watt). Include the BOM in your project submission

and also upload your BOM to Brightspace Assignments. The BOM must be received

by Wednesday, October 4 at noon. Use the BOM form posted on Brightspace./nAFFENS Anderd Hedar Val

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