Common Source JFET Amplifier
Equipment
1. DC Power Supply and Function Generator
2. Multimeter and Oscilloscope
Materials
1. 2N5458 JFET Transistor
2. (1)1.5 kΩ, (1) 4.7 kΩ, (1) 10 kΩ (1) 100 kΩ Resistors
3. (2) 10 μF and (1) 1000 μF Capacitors
Procedure
1. First create the circuit shown in Figure 9-1, and measure and record IDss. (Remember loss occurs when VGS = 0V)
2. To measure VGS(off), create the circuit in Figure 9-2 and place an ammeter in series to measure ID, and vary VGG until ID becomes zero. This is the value of VGS(off) for your transistor.
Figure 9-2
3. Measure and record the value of all resistors in Figure 9-3 (next page).
4. On a breadboard, construct the dc portion of the circuit shown in Figure 9-3 and measure ID and VGS.
5. Add the ac portion of the amplifier in Figure 9-3 and measure voltage gain (Oscilloscope: Vin -Channel 1 and Vout - Channel 2) and take a screenshot.
Figure 9-3
Data Analysis:
1. Using the data recorded above, theoretical knowledge, and EXCEL (or graphing equivalent software), create the Universal Transfer Characteristic Curve (look in your book/notes if you do not remember what this is) for your transistor and plot your dc load line.
2. Calculate the voltage gain of your circuit and compare it to measured gain.
Submittal:
1. Lab Cover Sheet (filled in appropriately)
2. Title Page
3. Objective - be original and thorough
4. Procedure - this may be completed in steps
5. DATA section including:
a. Circuits - do not use the instructor's drawings
b. Calculations
c. All measured data from this lab (table or as you see fit)
d. Graph
6. DISCUSSION
7. CONCLUSION