PSPICE EXERCISES:
1. Draw the circuit shown in Figure 7.5 with no load resistor, using your actual resistor values, and V, set to 12V (use the VDC component). Simulate the circuit to calculate the bias points. If the node voltages are not shown:
Figure 7.5:
30k
Go to <Analysis> Go to <Display Results on Schematic> Place a V before <Enable>. Place a V before Enable Voltage Display> and/or Enable Current Display
R4
50k
20k
R1
R3
What is the open circuit voltage where R2 is shown? This is V2. Record your value and print your schematic.
12V
R2 20k
R1
2. Estimate R using the following two methods:
Vs
a Determine I by deactivating V2 with a short and using a voltage source, Vt, in place of the load. Simulate the circuit to calculate the bias points, and show the branch currents on the schematic. What is the current out of the test voltage, It? Record your value and calculate R using Equation (7.5). Print your schematic.
B
(7.5)
VTest
Actual Resistor Values
R1 = 50.54k Ohms R2 = 19.92k Ohms R3 = 19.83k Ohms R4 = 29.55k Ohms
b Determine I by placing a 1 resistor across the load. With a wire drawn in PSpice for a short, it will not give you the current through it. Simulate the circuit to calculate the bias points, and show the branch currents on the schematic. What is the current through the load resistor, Is? Record your value and calculate R using Equation (7.4). Print your schematic. (7.4) Vrh RTn Rp Is.c.
3. Repeat procedures 1 and 2 with R2 replaced with a short (wire V2). Irest Is.c.
