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 I_Dss. (Remember loss occurs when V_GS = 0V)

2. To measure V_GS(off), create the circuit in Figure 9-2 and place an ammeter in series to measure I_D, and vary V_GG until I_D becomes zero. This is the value of V_GS(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 I_D and V_GS.

5. Add the ac portion of the amplifier in Figure 9-3 and measure voltage gain (Oscilloscope: V_in -Channel 1 and V_out - 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