Aim:To study the operation of half wave rectifier.
To find is:1-Ripple Factor.
2-Efficiency.
3-Percentage Regulation.
Components:Name
Quantity
1
1
Diodes 1N4007(Si)
Resistor 1kΩ
Equipments:Name
CRO
CRO probes
Digital Ammeter
Range
Quantity
(0-20)MHz
2
1
1
1
200mA
Digital Voltmeter
Transformer
Connecting Wires
0-20V
220V/9V, 50Hz
1
Theory:The Half-Wave Rectifier:A diode is connected to an ac source that provides the
input voltage, and to a load resistor, forming a halfwave rectifier, As in the following figure:-
When the sinusoidal input voltage goes positive, the
diode is forward-biased and conducts current through the
load resistor, As in the following figure:-
The current produces an output voltage across the load,
which has the same shape as the positive half-cycle of
the input voltage.
2
When the input voltage goes negative during the second
half of its cycle, the diode is reverse-biased, In this case
no current, so the voltage across the load resistor is zero,
As in the following figure:-
The net result is that only the positive half-cycles of the
ac input voltage appear across the load.
Effect of Diode barrier potential on HalfWave Rectifier Output Voltage:diode barrier potential is taken into account, During the
positive half-cycle, the input voltage must overcome the
barrier potential before the diode becomes forwardbiased, This results in a half-wave output voltage with a
peak value that is 0.7V less than the peak value of the
input voltage, As in the following figure:-
3
When you work with diode circuits, it is often practical
to neglect the effect of barrier potential when the peak
value of the applied voltage is much greater (at least ten
times) than the barrier potential.
Ripple Factor:Ripple factor is defined as the ratio of the effective value
of AC components to the average DC value. It is denoted
by the symbol " γ".
Rectification Factor:The ratio of output DC power to input AC power is
defined as efficiency.
ƞ
4
Circuit Diagram:Half Wave Rectifier:-
Fig.1:Circuit diagram of Half-wave rectifier
Procedure:Half Wave Rectifier:1-Connect the circuit as shown in the fig.1.
2-Connected the multimeter across the 1kΩ load.
3-Measure the AC and DC voltages by setting
multimeter to ac and dc mode respectively.
5
4-Now calculate the ripple factor using the following
formula.
5-Connect the CRO channel-1 across input and channel2 across output i.e load and Observe the input and output
Waveforms.
6-Now calculate the peak voltage of input and output
waveforms and also the frequency.
Observations:Input signal
RL
Output Signal
VAC(V) VDC(V) Ripple Factor
10kΩ
6
Vm p-p(v)
Frequency(Hz)
Vm p-p(v)
Frequency(Hz)
230
50
25
50
Calculations:1-Ripple Factor =____________.
2-Percentage Regulation =_____________.
Expected Waveforms:-
7
8
9
Result:1-Half Wave rectifier characteristics are studied.
2-Ripple factor of half wave rectifier =__________.
3- Regulation of half wave rectifier =__________.
Viva Questions:1-What is a rectifier?
Answer:A rectifier is an electrical device composed of one or
more diodes that converts alternating current (AC) to
direct current (DC), A diode is like a one-way valve that
allows an electrical current to flow in only one direction,
This process is called rectification.
2-What is a ripple factor?
Answer:The ratio of r.m.s value of ac component to the dc
component in the rectifier output is known as ripple
factor.
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3-What is a efficiency?
Answer:The ratio of dc power output to the applied input ac
power is known as rectifier efficiency.
Rectifier efficiency ƞ=
4-What is PIV?
Answer:Peak Inverse Voltage (PIV) is an important parameter of
a diode,It is the maximum voltage that can be safely
applied to the diode in its reverse direction without
breakdown.
5-What are the applications of rectifier?
Answer:1- The primary application of the rectifier is to derive DC
power from AC power.
2- Rectifiers are used inside the power supplies of almost
all electronic equipment, In power supplies, the rectifier
is normally placed in series following the transformer, a
smoothing filter and possibly a voltage regulator.
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6-Given some rectifications technologies?
Answer:Synchronous rectifier, Vibrator, Motor-generator set,
Electrolytic.
7-What is the efficiency of beidge rectifier?
Answer:The maximum rectifier efficiency of a bridge rectifier is
81.2%.
The reference of the theory:Electronics Fundamentals Circuits, Devices and
Application.
Thomas L. Floyd David L. Buchla
Eighth Edition
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