16. Semiconductor Devices
p-n Junction Diode as a Rectifier
PN Junction Diode || VI Characteristics of Diode with Animation || Basic Electronics - Bing
video
The conversion of AC voltage into a DC voltage is called
rectification. An electronic circuit which rectifies AC voltage is called
rectifier.
Block diagram simple rectifier circuit with respective output
wave form. Describe the wave forms.
*Write an explanation with the help of diagram…
There are two types of rectifier circuits, 1) half wave rectifier and 2)
full wave rectifier.
Half Wave Rectifier
Q. What is a half- wave rectifier? With a neat circuit
diagram, explain the use/ working of a junction diode as a
half-wave rectifier. Draw the input and output voltage
waveforms. 4M
, OR
Q. Draw the circuit diagram of a half-wave rectifier. Explain
its working. What is the frequency of ripple in its output?
Fig. Circuit diagram of a half wave rectifier.
The secondary coil AB of a transformer is connected in series
with a diode D and the load resistance RL. The use of
transformer has two advantages. First, it allows us to step up or
step down the AC input voltage as per the requirement of the
circuit, and second it isolates the rectifier circuit from the mains
supply to reduce the risk of electric shock.
The AC voltage across the secondary coil AB changes its
polarities after every half cycle. When the positive half cycle
begins, the voltage at the point A is at higher potential with
respect to that at the point B, therefore, the diode (D) is forward
biased.
It conducts (works as a closed switch) and current flows through
the circuit. When the negative half cycle begins, the potential at
the point A is lower with respect to that at the point B and the
diode is reverse biased, therefore, it does not conduct (works as
an open switch). No current passes through the circuit. Hence,
the diode conducts only in the positive half cycles of the AC
, input. It blocks the current during the negative half cycles. In
this way, current always flows through the load RL in the same
direction for alternate positive half cycles.
Waveform of input and output signals for half wave rectifier.
Hence a DC output voltage obtained across RL is in the form of
alternate pulses.
Full Wave Rectifier:
Q. What is a full- wave rectifier? With a neat circuit
diagram, explain the use/ working of two junction diode as a
full-wave rectifier. Draw the input and output voltage
waveforms. 4M
OR
Q. Draw the circuit diagram of a full-wave rectifier. Explain
its working. 3M
In a full wave rectifier, current flows through the load in the
same direction during both the half cycles of input AC voltage.
This is because, the full wave rectifier circuit consists of two
diodes conducting alternately as shown in fig . The circuit
consists of a center tapped transformer and diodes D1 and D2
, Circuit diagram for full wave rectifier.
The diodes D1 and D2 are connected such that D1 conducts in the
positive half cycle and D2 conducts in the negative half cycle of
the input voltage.
During the positive half cycle of the input voltage, the point A is
at a higher potential than that of the point B and the diode D1
conducts.
The current through the load resistance RL follows the path
APQRC as shown in Fig. During the negative half cycle of the
input voltage, point B is at higher potential than point A and the
diode D2 conducts. The current through the load resistance RL
follows the path BPQRC.
Thus, the current flowing through the load resistance is in the
same direction during both the cycles.
The input and output waveforms of a full wave rectifier are
shown in Fig. First waveform is input AC. The second wave
form shows the output when the diode D1 conducts and the third
waveform shows the output when diode D2 conducts. The fourth
waveform shows the total output waveform of the full wave
rectifier.
p-n Junction Diode as a Rectifier
PN Junction Diode || VI Characteristics of Diode with Animation || Basic Electronics - Bing
video
The conversion of AC voltage into a DC voltage is called
rectification. An electronic circuit which rectifies AC voltage is called
rectifier.
Block diagram simple rectifier circuit with respective output
wave form. Describe the wave forms.
*Write an explanation with the help of diagram…
There are two types of rectifier circuits, 1) half wave rectifier and 2)
full wave rectifier.
Half Wave Rectifier
Q. What is a half- wave rectifier? With a neat circuit
diagram, explain the use/ working of a junction diode as a
half-wave rectifier. Draw the input and output voltage
waveforms. 4M
, OR
Q. Draw the circuit diagram of a half-wave rectifier. Explain
its working. What is the frequency of ripple in its output?
Fig. Circuit diagram of a half wave rectifier.
The secondary coil AB of a transformer is connected in series
with a diode D and the load resistance RL. The use of
transformer has two advantages. First, it allows us to step up or
step down the AC input voltage as per the requirement of the
circuit, and second it isolates the rectifier circuit from the mains
supply to reduce the risk of electric shock.
The AC voltage across the secondary coil AB changes its
polarities after every half cycle. When the positive half cycle
begins, the voltage at the point A is at higher potential with
respect to that at the point B, therefore, the diode (D) is forward
biased.
It conducts (works as a closed switch) and current flows through
the circuit. When the negative half cycle begins, the potential at
the point A is lower with respect to that at the point B and the
diode is reverse biased, therefore, it does not conduct (works as
an open switch). No current passes through the circuit. Hence,
the diode conducts only in the positive half cycles of the AC
, input. It blocks the current during the negative half cycles. In
this way, current always flows through the load RL in the same
direction for alternate positive half cycles.
Waveform of input and output signals for half wave rectifier.
Hence a DC output voltage obtained across RL is in the form of
alternate pulses.
Full Wave Rectifier:
Q. What is a full- wave rectifier? With a neat circuit
diagram, explain the use/ working of two junction diode as a
full-wave rectifier. Draw the input and output voltage
waveforms. 4M
OR
Q. Draw the circuit diagram of a full-wave rectifier. Explain
its working. 3M
In a full wave rectifier, current flows through the load in the
same direction during both the half cycles of input AC voltage.
This is because, the full wave rectifier circuit consists of two
diodes conducting alternately as shown in fig . The circuit
consists of a center tapped transformer and diodes D1 and D2
, Circuit diagram for full wave rectifier.
The diodes D1 and D2 are connected such that D1 conducts in the
positive half cycle and D2 conducts in the negative half cycle of
the input voltage.
During the positive half cycle of the input voltage, the point A is
at a higher potential than that of the point B and the diode D1
conducts.
The current through the load resistance RL follows the path
APQRC as shown in Fig. During the negative half cycle of the
input voltage, point B is at higher potential than point A and the
diode D2 conducts. The current through the load resistance RL
follows the path BPQRC.
Thus, the current flowing through the load resistance is in the
same direction during both the cycles.
The input and output waveforms of a full wave rectifier are
shown in Fig. First waveform is input AC. The second wave
form shows the output when the diode D1 conducts and the third
waveform shows the output when diode D2 conducts. The fourth
waveform shows the total output waveform of the full wave
rectifier.
