Half-wave Rectifier:
In half wave rectifier circuit operates by using a diode to prevent one half of an alternating current
waveform to pass. As a result only part (typically half) of the waveform passes and the waveform is rectified.
A half-wave rectifier is the simplest form of the rectifier and requires only one diode for the construction
of a half wave rectifier circuit.
A half wave rectifier circuit consists of three main components as follows:
A diode
A transformer
A resistive load
Fig.1. Half-wave Rectifier
Fig.1. shows the circuit where a single crystal diode acts as a half wave rectifier. The A.C supply to be rectified
is applied in series with the diode and load resistor. The A.C supply given through a transformer. The output
D.C is taken across the load resistor.
Operation of Half-Wave Rectifier
The A.C voltage across the secondary winding AB changes polarities after every half-cycle. During the
positive half cycle of input A.C voltage end A becomes positive with respect to end B. This makes the diode
forward biased and hence it conducts current.
During the negative half cycle end A becomes negative w.r.t end B. Under this condition the diode is
reverse biased and it conducts no current. Therefore current flows through the diode during positive half cycles
of input A.C voltages only, it blocks during the negative half cycles.
In this way current flows through load resistor always in the same direction. Hence D.C. output is
obtained across load resistor.
Efficiency of half-wave rectifier:
The ratio of d.c power output to the applied input a.c. power is known as rectifier efficiency i.e
d.c output power
Rectifier Efficiency , ղ =
Input a.c.power
Consider a half wave rectifier is as shown in fig. Let V = Vm Sinθ be the alternating voltage that appears across
the secondary winding. Let rf and RL be the diode resistance and load resistance. The diode conducts during
positive half cycles of a.c. supply while no current conduction takes place during negative half-cycles.
In half wave rectifier circuit operates by using a diode to prevent one half of an alternating current
waveform to pass. As a result only part (typically half) of the waveform passes and the waveform is rectified.
A half-wave rectifier is the simplest form of the rectifier and requires only one diode for the construction
of a half wave rectifier circuit.
A half wave rectifier circuit consists of three main components as follows:
A diode
A transformer
A resistive load
Fig.1. Half-wave Rectifier
Fig.1. shows the circuit where a single crystal diode acts as a half wave rectifier. The A.C supply to be rectified
is applied in series with the diode and load resistor. The A.C supply given through a transformer. The output
D.C is taken across the load resistor.
Operation of Half-Wave Rectifier
The A.C voltage across the secondary winding AB changes polarities after every half-cycle. During the
positive half cycle of input A.C voltage end A becomes positive with respect to end B. This makes the diode
forward biased and hence it conducts current.
During the negative half cycle end A becomes negative w.r.t end B. Under this condition the diode is
reverse biased and it conducts no current. Therefore current flows through the diode during positive half cycles
of input A.C voltages only, it blocks during the negative half cycles.
In this way current flows through load resistor always in the same direction. Hence D.C. output is
obtained across load resistor.
Efficiency of half-wave rectifier:
The ratio of d.c power output to the applied input a.c. power is known as rectifier efficiency i.e
d.c output power
Rectifier Efficiency , ղ =
Input a.c.power
Consider a half wave rectifier is as shown in fig. Let V = Vm Sinθ be the alternating voltage that appears across
the secondary winding. Let rf and RL be the diode resistance and load resistance. The diode conducts during
positive half cycles of a.c. supply while no current conduction takes place during negative half-cycles.
