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Electronics Lab1

This lab document outlines an experiment to determine the I-V characteristic curve of a diode by measuring current and voltage values across a diode under forward and reverse bias conditions, and then using load line analysis to determine the operating point of a diode in a circuit with a resistor. Students are provided procedures and tables to record diode voltage and current measurements as the supply voltage is varied to construct the diode's characteristic curve and analyze its operation in different biasing conditions.

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khulood
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33 views6 pages

Electronics Lab1

This lab document outlines an experiment to determine the I-V characteristic curve of a diode by measuring current and voltage values across a diode under forward and reverse bias conditions, and then using load line analysis to determine the operating point of a diode in a circuit with a resistor. Students are provided procedures and tables to record diode voltage and current measurements as the supply voltage is varied to construct the diode's characteristic curve and analyze its operation in different biasing conditions.

Uploaded by

khulood
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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ELE 2403

Electronics I

Learning Outcome 1
Lab 1: I-V Characteristics for a Diode

Student Name(s) Student ID Number


Khulood Albraiki H00413574
Aysha Almarar H00415854
Lab Instructor Eng. Shaily Khurana
Introduction:

Let us know about the diode first. An electrical device with two terminals that conducts
electricity mostly in one direction is called a diode. On one end it has a high resistance
and on the other a low resistance.

The diode has three types, but in this lab we will work on:
1. Forward-biased diode.
2. Reverse-biased diode.

As rectifiers, signal limiters, voltage regulators, switches, signal modulators, signal


mixers, signal demodulators, and oscillators, diodes are a versatile electrical
component.

Objective:
In this activity you will determine the I-V characteristic curve for a diode. You will use the
results to determine the current through the diode in a simple series diode circuit using the
load line technique.

𝑉𝑠 =𝑉𝑅 +𝑉𝐷
𝑉𝑅
𝐼𝑅 =
𝑅
Activity:
You will complete the unknown measurements in the tables below.

Material needed

1- Diode 1N4001
2- Resistor 1K
3- Wires
4- Breadboard
Part I derive V-I Characteristic for a Diode

Procedure

1. Connect the circuit shown in Fig. 1


2. Set Vs to zero volt.
3. Increase Vs to meet the values of ID as in Table 1.
4. When done, reconnect the circuit in Fig. 2
5. Repeat steps 2-3 above, and fill in Table 2

Fig. 1

Table 1
𝐸𝐴 DIODE VOLTAGE (V) DIODE CURRENT (𝑚𝐴)
0 0 0
0.2 0.23 0
0.4 0.45 0.03
0.6 0.60 0.92
0.7 0.61 1.19
0.8 0.64 2.34
0.9 0.65 2.63
1 0.67 3.64
2 0.72 14.31
4 0.77 32.8
6 0.79 53.3
Draw the curves of ID-VD on the diagram below

Comments: When there is positive voltage across the diode, the diode is "on,"
allowing current to flow through. For the current to be meaningful, the voltage
must be higher than the forward voltage (VF).

Fig. 1.b
Table 2
𝐸𝐴 DIODE VOLTAGE (V) DIODE CURRENT (𝑚𝐴)
0 0 0
5.0 5.07 0
10.0 10.07 0
15.0 15.05 0
20.0 20.01 0
25.0 25.0 0
30.0 30.0 0

Comments: This is the diode's "off" mode, where the voltage is greater than -VBR but
less than VF. The diode is off and current flow is largely inhibited in this mode. Reverse
saturation current, which is very tiny (on the order of nA) and can flow through a diode
in the other direction.

Part II Load Line

1. Construct the circuit shown below.


2. Measure the values of ID and VD
3. Draw the load line on the I-V characteristic curves you drew earlier, find
the intersection and evaluate the Q-points

Measured ID = 42.5 mA

Measured VD = 0.7V
Conclusion:

Ideally, diodes will simply operate as a short-circuit if current is moving forward or


completely block any and all reverse current flow. Sadly, actual diode behavior falls
short of ideal. When conducting forward current, diodes do use some power, and they
can't completely block off reverse current. Diodes in the real world are a little more
complicated, and they all have special features that determine how they function in
practice.

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