This document provides an overview of rectifiers, which are electrical devices that convert alternating current (AC) to direct current (DC) using diodes. It discusses the basic components and functioning of half-wave and full-wave rectifiers, including their advantages and disadvantages. Specifically, it explains that rectifiers use diodes to allow current to flow in only one direction, converting the alternating current of AC to the pulsing DC output of a rectifier. It also covers bridge rectifiers and their applications in converting AC power to DC power for various devices.

1. Basic
Electronics
Course instructor
Rida Shifa

2. Rectifier
 Rectifier is a device which is used for converting
alternating current/voltage into direct current
/voltage.
 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.
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3. Applications of rectifier
 A rectifier can take the shape of several
different physical forms such as solid-state
diodes, vacuum tube diodes, mercury arc
valves, silicon-controlled rectifiers and various
other silicon-based semiconductor switches
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4. Usage in Devices
Rectifiers are used in various devices, including:
 DC power supplies
 Radio signals or detectors
 A source of power instead of generating current
 High-voltage direct current power transmission
systems
 Several household appliances use power rectifiers
to create power, like notebooks or laptops, video
game systems and televisions.
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5. Power diode
 Power Diode is the two terminal(namely anode and
cathode) two layer(P-N) device which is used in most of
the power electronics circuits.
 The power semiconductor diode is similar to low power
PN junction diode (signal diode).
 In fact, power diode is more complex in structure and
in operation than their low power counterparts.
 This complexity happens because low power device
must be modified to make them suitable for high power
applications
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6. Recalling the PN junction
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7. Ripple Factor
 Ripple factor (γ) may be defined as the ratio
of the root mean square (rms) value of
the ripple voltage to the absolute value of the
DC component of the output voltage, usually
expressed as a percentage.
 However, ripple voltage is also commonly
expressed as the peak-to-peak value.
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8. Ripple Factor
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9. Biasing
 Biasing in electronics means establishing
predetermined voltages or currents at various
points of an electronic circuit for the purpose
of establishing relationships between the
voltage and current in electronic components
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10. Biasing types
 When we connect p-type region of a junction with
the positive terminal of a voltage source and n-
type region with the negative terminal of the
voltage source, then the junction is said to be
forward biased
 When positive terminal of a voltage source is
connected to the n-type region and the negative
terminal of the source is connected to the p-type
region then the p-n junction is said to be in
reverse biased condition
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11. Forward biasing
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12. Reverse biasing
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13. PN junction as Rectifier
 The main application of p-n junction diode is in
rectification circuits.
 Diode rectifier gives an alternating voltage which
pulsates in accordance with time.
 The filter smoothens the pulsation in the voltage
and to produce d.c voltage.
 There are two primary methods of diode
rectification:
 Half Wave Rectifier
 Full Wave Rectifier
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14. Half wave rectifier
 The input power supply may be either a single-
phase or a multi-phase supply with the simplest of
all the rectifier circuits being that of the Half Wave
Rectifier.
 The power diode in a half wave rectifier circuit
passes just one half of each complete sine wave
of the AC supply in order to convert it into a DC
supply. Then this type of circuit is called a “half-
wave” rectifier because it passes only half of the
incoming AC power supply
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15. Working
 The half wave rectifier has both positive and
negative cycles. During positive half of the input,
the current will flow from positive to negative
which will generate only positive half cycle of the
a.c supply.
 When a.c supply is applied to the transformer, the
voltage will be decreasing at the secondary
winding of the diode.
 All the variations in the a.c supply will reduce and
we will get the pulsating d.c voltage to the load
resistor.
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16. Pictorial Representation
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17. Advantages
 Though a half wave rectifier is not a good
choice in most cases, it is cheap, and simple
to construct.
 The reason why it is cheap is because it
needs a low number of components, while
simple is because its circuit design is straight
forwardness.
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18. Disadvantages
 The output current in the load contains, in addition to dc
component, ac components of basic frequency equal to that
of the input voltage frequency.
 Ripple factor is high and an elaborate filtering is, therefore,
required to give steady dc output.
 The power output and, therefore, rectification efficiency is
quite low.
 Transformer utilization factor is low
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19. Applications
 In practice, the half-wave rectifier is used most
often in low-power applications.
 The output amplitude is less than the input
amplitude, there is no output during the negative
half cycle so half the power is wasted and the
output is pulsed DC resulting in excessive ripple.
 To overcome these disadvantages a number
of Power Diode are connected together to
produce a Full Wave Rectifier
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20. Full wave rectifier
 Full wave rectifier utilizes both halves of each a.c
input.
 When the p-n junction is forward biased, the
diode offers low resistance and when it is
reversing biased it gives high resistance.
 The circuit is designed in such a manner that in
the first half cycle if the diode is forward biased
then in the second half cycle it is reverse biased
and so on.
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21. Pictorial Representation
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22. Advantages
 The rectification efficiency is double than half
wave rectifier.
 Ripple factor is less and ripple frequency is
doubled hence easy to filter out.
 DC output voltage and current is higher hence
output power is higher.
 Better transformer utilization factor
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23. Disadvantages
 Requires center tap transformer.
 Requires two diodes compared to one diode in half
wave rectifier.
 It is expensive to manufacture a center tapped
transformer
 The output voltage is half of the secondary voltage, as
each diode utilizes only one half of the transformer
secondary voltage.
 The PIV (peak inverse voltage) of a diode used twice
that of the diode used in the half wave rectifier, so the
diodes used must have high PIV.
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24. Efficiency
 The rectifier converts the AC to DC, which
isn't to say that the voltage isn't varying, it's
just that the current isn't going both ways.
 Full wave rectifiers are definitely more better
than half wave rectifiers because they give
you power during both halves of the cycle.
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25. Applications
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 Bridge is a type of electrical circuit.
 Bridge rectifier is a type of rectifier in which
diodes were arranged in the form of a bridge.
 This provides full wave rectification and is of
low cost

26. Bridge Rectifier
 A bridge rectifier is an arrangement of four or
more diodes in a bridge circuit configuration
which provides the same output polarity for
either input polarity.
 It is used for converting an alternating current
(AC) input into a direct current (DC) output.
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27. Bridge Rectifier
 A bridge rectifier provides full-wave
rectification from a two-wire AC input,
therefore resulting in lower weight and cost
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28. Bridge Rectifier
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29. Types
 There are many different kinds of bridge
rectifiers and at Future Electronics we stock
many of the most common types categorized
by maximum average rectified current,
maximum reverse voltage, maximum peak
current, forward voltage, packaging type and
maximum reverse current.
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30. Size
 The most common sizes for maximum average
rectified current are 1A, 1.5 A, 4 A, 25 A and 35 A.
 We also carry bridge rectifiers with maximum
average rectified current as high as 1000 A.
 Forward voltage can range from 450 mV to 1.1 kV,
with the most common bridge rectifier
semiconductor chips having a forward voltage of
1.1 V or 1 V.
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31. Bridge rectifier in future
 Future Electronics has a full selection of
bridge rectifier chips from several
manufacturers that can be used to design a
full wave bridge rectifier circuit, half wave
rectifier or any other type of circuits that may
require a bridge rectifier.
 Fairchild, IXYS, Micro Commercial Comp or
Vishay, among other manufacturers.
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32. Applications
 The primary application of bridge rectifiers is
to transform an AC supply into DC power.
 Bridge rectifiers are also used for detecting
the amplitude of modulated radio signals.
 Rectifiers are also used to supply polarized
voltage for welding applications.
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33. Advantages
 The rectification efficiency of full-wave rectifier is double of
that of a half-wave rectifier.
 Higher output voltage, higher output power and higher
Transformer Utilization Factor in case of full-wave rectifier.
 The ripple voltage is low and of higher frequency in case of
full-wave rectifier so simple filtering circuit is required
 No center tap is required in the transformer secondary so in
case of a bridge rectifier the transformer required is simpler. If
stepping up or stepping down of voltage is not required,
transformer can be eliminated even.
 For a given power output, power transformer of smaller size
can be used in case of the bridge rectifier
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34. Disadvantages
 It requires four diodes.
 The use of two extra diodes cause an
additional voltage drop thereby reducing the
output voltage.
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35. Daily life
 A rectifier is an electrical device that converts
alternating current (AC), which The best
example of rectifier that is used in our daily
life is in the mobile phone charge
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36. Overview
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