DEE20023 – SEMICONDUCTOR DEVICES PW1
DEPARTMENT OF ELECTRICAL ENGINEERING
PRACTICAL WORK : 1
TITLE : STUDYING AND UNDERSTANDING THE CHARACTERISTICS OF DIOD
OUTCOMES :
1. To identify the physical structure of diodes
2. To identify the legs of diode by using physical structure and multimeter
3. To test the effect when the diode is forward biased or reverse biased
THEORY
Diode is an electronic component which has two legs; Anode (positive) and Cathode (negative). It’s main
function is to limit the flow of the one way current when it is forward biased (from Anode to
cathode).Types of the diode is depend on it usage. Examples; Signal Diode and Power Diode. Others are
LED and Zener Diode.
P N
Anode Cathode A C
A C
(+) (-)
Physical Diode Structure Schematic Symbol Physical Structure
Biased Voltage For Diode.
Voltage that is given for diode.
i. Forward Bias
When the positive supply is connected to Anode and negative supply is connected to Cathode
Characteristics : a. Lower Depletion Resistance(RD)
b. Existence of the forward current
ii. Reverse Bias
When the negative supply is connected to Anode and positive supply is connected to Cathode
Characteristics : a. Higher Depletion Resistance(RD) (infinity).
b. No current.
1
DEE20023 – SEMICONDUCTOR DEVICES PW1
COMPONENTS / EQUIPMENTS :
i. Several types of diode
ii. Multimeter
PROCEDURES I:
Physical Structure/identify the legs of diode.
a. Scetch the structure of the given diode.
b. Identify the legs of diode and mark on your scetch.
c. Fill in the Table 1.0
PROCEDURES II:
Identify the legs of diode using Ohm Meter. Forward Bias and Reverse Bias.
a. Adjust Multimeter (Ohm Meter) to the range X1 KOhm. Short two multimeter terminal and set
the 0 adjuster.
b. Connect red test probe Ohm Meter to the one of the leg of diode (Point A) and another black test
probe to another leg(Point B). State the result on Ohm Meter, types of bias and identify the legs
of diodeon Table 2.0. Repeat the step by changing the Meter Ohm terminal.
c. Repeat (b) by using another diode.
Note:
Positive terminal (+) marked on Ohm Meter is a negative terminal (-) for the battery in the meter and
negative terminal (-) marked on Ohm Meter is a positive terminal (+) for the battrey in the meter.
2
DEE20023 – SEMICONDUCTOR DEVICES PW1
RESULTS:
Diode 1 Diode 2 Diode 3
Diode Number or
Label
Physical Shape /
Label the lead
(Table 1.0)
Diode Terminal Meter Ohm Types of bias Legs of diode
Number Colour Result (forward/reverse)
or Label ( Red / Black) (↓ / )
Red (A) Black A=
(B)
1
Black Red (B) B=
(A)
Red (A) Black A=
(B)
2 Black Red (B) B=
(A)
Red (A) Black A=
3 (B)
Black Red (B) B=
(A)
Table 2.0
3
DEE20023 – SEMICONDUCTOR DEVICES PW1
DISSCUSSION
1. Explain how to identify anode and cathode terminals of diode. (4 marks)
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2. Explain how to determine the condition (good or bad) of a diode. (4 marks)
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3. If high resistance, the diode is in _________________bias
If low resistance, the diode is in _________________bias (2 marks)
CONCLUSION:
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(10 marks)
