EE 212 - EXP 3 Raporu - junction field effect transistor (JFET) drain output characteristic PDF

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junction field effect transistor (JFET) drain output characteristic...

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EE 212 ELECTRONIC CIRCUITS 1 EXPERIMENT 3 Junction Field Effect Transistor (JFET) Drain output characteristic

1.OBJECTIVES Our purpose learning JFET Drain output characteristic in Common Dource (CS) configuration. We use JFET in this experiment because that can be use as switches, amplifiers or voltage-controlled resistors and we use JFET for voltage-controlled. We observed this situation using supply voltage for measured JFET’s voltage and current how change. We learned JFET’s voltage and current when the difference between decreasing or incresing supply voltage’s V1 and

V2. Before describing the experiment, we need to know the characteristics of JFET.

BACKGROUND JFET’s characteristic properties:

-

N-channel and P channel JFETs and connection legs are shown in the figures below.

- JFET’s are of two types, namely N-channel JFETs and P-channel JFETs. Generally N channel JFETs are more preferred than P-channel.

- They are three-terminal semiconductor devices that can be use as switches, amplifiers, or voltage-controlled resistors.

In the JFET output characteristics shown in Figure below, we know that the Drain current (iD) very little change. The increase the current is balanced, when increase in voltage between Source and Drain (VDS).

2.METHODOLOGY

Equipments: - JFET (BF 245 or BR 5459) - Two resistors; 1 kohm each - Breadboard - Digital Multimeter - Dc Power Supply

FOR V-GS = 0V Firstly we designed the circuit for Vgs = 0V on the breadboard. We use two resistors and JFET(BF 245 2N 5449), Dc Power Supply( -25V , 25V) and we connected JFET’s G leg’s with resistor’s one leg (1 kohm) and this resitor’s independent leg’s with Dc Power Suplly’s negative source (V1 – V-GS) then, we connected JFET’s D leg’s with resistor’s one leg ( 1 kohm) and this resistor’s

independent leg’s with Dc Power Supply’s positive source (V2). Finally, we connected JFET’s S leg’s with ground. We set V-GS = 0V with the help of the suplly voltage V1 is and we set vary V-DS from 0V to 10V in step of 1V. After that we measured voltage JFET’s D leg’s and S leg’s between by multimeter every from 0V to 10V in step of 1V. After that we break JFET’s D leg’s and break depends on this resistor’s leg for measured current and we used multimeter between JFET’s D leg’s and resitor’s leg.

VGS = 0V

For

VDS (Volts)

I-D (mA)

4

2,74

5,41

3,34

6,5

3,48

7,56

3,55

8,60

3,58

9,64

3,6

10,64

3,62

11,64

3,64

12,64

3,65

13,64

3,65

1V

CIRCUIT DIAGRAM :

FOR V-GS = -1V For circuit diagram, every step is same for V-GS = -1V, but also we change and set V-GS= -1 V on the Dc Power Supply. We change and we set V-GS = -1V with the help of the suplly voltage V1 is and we set vary V-DS from 0V to 10V in step of 1V. After that we measured voltage JFET’s D leg’s and S leg’s between by multimeter every from 0V to 10V in step of 1V. After that we break JFET’s D leg’s and break depends on this resistor’s leg for measured current and we used multimeter between JFET’s D leg’s and resitor’s leg.

VGS = -1V

For 1v

VDS (Volts)

I-D (mA)

1,50

0,50

2,60

0,54

3,50

0,56

4,50

0,57

5,57

0,58

6,57

0,59

7,58

0,60

8,58

0,61

9,58

0,61

10,58

0,61

RESULTS AND DISCUSSION :

As a result, we learned V-GS’s ( for V-GS =0V) V-DS (V) and I-D(mA) values larger than V-GS = -1V when V2 = 1 V so we know that JFET’s V-DS and I-D value growed when JFET’s V-GS > before V-GS. When V-GS = -1 V ID current very little increasing but I-D current value increasing big enough every step 1 V. JFET’s characteristic properties give us very important input voltage’s value because every V-G (input) voltage increasing who is making enough increases for I-D current for (V-GS > V-GS before)....