2. WHAT IS A RECTIFIER ??
A Rectifier is an electrical device that
converts alternating current AC into
direct current DC.
Types of Rectifiers
• There are two main types of rectifier
circuits.They are
• Half-wave Rectifier
• Full-wave Rectifier
Alternating
current
Direct current
4. CENTER TAPPED FULL WAVE RECTIFIER
• A type of rectifier which is designed by using
two diodes as well as a center tapped
transformer for converting the whole AC
signal to DC is called center tapped FWR.
This is called as “full wave center tapped”
because there are two full cycles in one
complete cycle of AC voltage.This means that
it produces twice as much DC voltage as a
half-wave rectifier would produce from an
equivalent AC source.
• The voltage at the tapped mid-point is zero.
Therefore it forms a neutral point.
5. During the Positive Half Cycle of the AC
input
• The top end of the secondary winding
becomes positive, and the bottom end
becomes negative.
• Diode D1 becomes forward-biased
(conducts), and D2 is reverse-biased
(blocks).
• Current flows through D1, through the
load resistor (RL), and back to the center
tap.
WORKING OF A CENTER TAPPED FULL WAVE RECTIFIER
6. During the Negative Half Cycle of
the AC input:
• The polarity reverses, the bottom end
becomes positive, and the top end
becomes negative.
• Diode D2 conducts, and D1 blocks.
• So the current again flows through RL
in the same direction, maintaining
unidirectional output.
WORKING OF A CENTER TAPPED FULL WAVE RECTIFIER
7. WORKING OF A CENTER TAPPED FULL WAVE
RECTIFIER
Output Across Load:
The load receives current in the same
direction during both half-cycles.This
results in a full-wave rectified output
(pulsating DC).
8. WAVEFORMS OF FWR
• The first waveform represents an
input AC signal.
• The second waveforms, we can
conclude that the output current
produced at the load resistor is not
a pure DC but a pulsating DC. third
waveform represents the DC
signals produced by diode D1 and
diode D2.
• The last waveform represents the
total output DC current produced
by diodes D1 and D2.
• From the above
9. BRIDGE FULL WAVE RECTIFIER
• A bridge rectifier is a circuit that converts AC
to DC using four diodes arranged in a bridge
configuration
• Bridge rectifiers are similar to half-wave
rectifiers and full-wave rectifiers.They use four
diodes(D1, D2, D3, and D4).The input is supplied
across terminals A and B, and the output is
collected across a load resistor (RL) connected
between terminals C and D.
• It works by allowing current to flow through
different pairs of diodes based on the input
polarity, ensuring the output polarity
10. WORKING OF A BRIDGE FULLWAVE
RECTIFIER
• When the positive half cycle of the input
supply is given, point P becomes positive
with respect to the point Q.
• This makes the diode D1 and D3 forward
biased while D2 and D4 reverse biased.
• These two diodes will now be in series
with the load resistor.
• Hence the diodes D1 and D3 conduct
during the positive half cycle of the input
supply to produce the output along the
load resistor.
11. WORKING OF A BRIDGE FULLWAVE
RECTIFIER
When the negative half cycle of the input
supply is given, point P becomes negative
with respect to the point Q.
• This makes the diode D1 and D3 reverse
biased while D2 and D4 forward biased.
• These two diodes will now be in series with
the load resistor.
• Hence the diodes D2 and D4 conduct during
the negative half cycle of the input supply to
produce the output along the load resistor.
12. THE CHARACTERISTICS OF THE FULL
WAVE RECTIFIER
• Ripple factor
• DC current
• Output DC voltage (VDC)
• Peak inverse voltage (PIV)
• Rectifier efficiency
• Root mean square (RMS) value of load current IRMS
• Root mean square (RMS) value of output load voltage VRMS
13. RIPPLE FACTOR
• The ripple factor is used to measure the amount
of ripples present in the output DC signal. A high
ripple factor indicates a high pulsating DC
signal while a low ripple factor indicates a low
pulsating DC signal.
• It is defined as the ratio of ripple voltage to the
pure DC voltage
RECTIFIER EFFICIENCY
• Rectifier efficiency is defined as the ratio of DC
output power to the AC input power.
• The rectifier efficiency of a full wave rectifier is
81.2%.
• efficiency of a full wave rectifier is twice that of the
half wave rectifier.
= output PDC / input PAC
η
14. PEAK INVERSE VOLTAGE (PIV)
• Peak inverse voltage or peak reverse voltage is
the maximum voltage a diode can withstand in
the reverse bias condition. If the applied voltage
is greater than the peak inverse voltage, the
diode will be permanently destroyed.
DC OUTPUT CURRENT
• D1 and diode D2 currents flow in the same
direction. So the output current is the sum of
D1 and D2 currents.
• The current produced by D1 is Imax / π and
• the current produced by D2 is Imax / π.
• Imax = maximum DC load current
The peak inverse voltage (PIV) =
2Vsmax
output current IDC = 2Imax / π
15. .
DC OUTPUT VOLTAGE
• The DC output voltage appeared at the
load resistor RL is given as
• Vmax = maximum secondary voltage
Root mean square (RMS) value of
load current IRMS
• The root mean square (RMS) value of
load current in a full wave rectifier is
VDC = 2Vmax /π
16. • Root mean square
(RMS) value of the
output load voltage
VRMS :
The root mean square (RMS)
value of output load voltage in
a full wave rectifier is
17. Advantages of Full-Wave Rectifier:
• Higher Efficiency – Utilizes both halves of the AC input, resulting in
better power conversion.
• Higher Average Output Voltage – Provides more DC output
compared to a half-wave rectifier.
• Smoother Output – With appropriate filtering, the output becomes
closer to pure DC.
• Better Transformer Utilization – Especially in bridge rectifiers (no
center tap needed).
18. Disadvantages of Full-Wave Rectifier
• Higher Voltage Drop – In bridge rectifiers, two diodes conduct at once,
leading to more voltage loss.
• Center-Tapped Transformer (for some types) – Center-tap full-wave
rectifiers require special transformers, which may not always be
available or economical.
• More Heat Generation – Due to higher current handling and multiple
diodes, it may require better heat dissipation.
