What is Full Wave Rectifier?
Full-wave rectifier circuits are
used for producing an output voltage or output current which is purely DC. The
main advantage of a full-wave rectifier over half-wave rectifier is that such
as the average output voltage is higher in full-wave rectifier, there is less
ripple produced in full-wave rectifier when compared to the half-wave
rectifier.
Working of Full Wave Rectifier
The 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.
Characteristics of Full Wave Rectifier
Following are the characteristics of full-wave rectifier:
Ripple Factor
Ripple factor for a full-wave rectifier is given as:
DC Current
Currents from both the diodes D1 and D2 are in the same direction when they flow towards load resistor RL. The current produced by both the diodes is the ratio of Imax to π, therefore the DC current is given as:
Where,
DC Output Voltage
DC output voltage is obtained at
the load resistor RL and is given as:
Where,
Vmax is the maximum secondary voltage
Form Factor
The form factor is the ratio of
RMS value of current to the output DC voltage. The form factor of a full-wave
rectifier is given as 1.11
Rectifier Efficiency
Rectifier efficiency is used as a
parameter to determine the efficiency of the rectifier to convert AC into DC.
It is the ratio of DC output power to the AC input power. The rectifier
efficiency of a full-wave rectifier is 81.2%.
Advantages of Full Wave Rectifier
- The rectifier efficiency of a full-wave rectifier is high
- The power loss is very low
- Number of ripples generated are less
Disadvantages of Full Wave Rectifier
- Very expensive
Types of Full Wave Rectifier
There are two main types of full-wave rectifiers, and they are:
- Two diodes full-wave rectifier circuit (requires a center-tapped transformer and is used in vacuum tubes)
- Bridge rectifier circuit (doesn’t require a centre-tapped transformer and is used along with transformers for efficient usage)
Applications of Full Wave Rectifier
Following are the uses of full-wave rectifier:
- Full-wave rectifiers are used for supplying polarized voltage in welding and for this bridge rectifiers are used.
- Full-wave rectifiers are used for detecting the amplitude of modulated radio signals.
