What is a Full Wave Rectifier?
A type of rectifier known as a full wave rectifier is one that transforms the AC signal's two halves into a pulsating DC signal. Full-wave rectifiers are used for the conversion of AC voltage to DC voltage whic hrequires multiple diodes to construct. The process of converting an AC signal to a DC signal is known as full wave rectification.
Electrical circuits called rectifiers convert alternating current (AC) to direct current (DC). If such rectifiers correct both the positive and negative half cycles of an input alternating waveform, they are full-wave rectifiers.
We can classify rectifiers into two types:
- Half Wave Rectifier
- Full Wave Rectifier
A large amount of power is lost when using a half-wave rectifier because only one half of each cycle is allowed to proceed while the other cycle is blocked. Furthermore, the half-wave rectifier's efficiency (40.6%) prevents us from using it for applications that require a constant and dependable DC output. A full wave rectifier is used to produce a more effective and reliable DC output.
A half-wave rectifier uses only the half wave of the input AC signal, whereas full wave rectifiers use the entire cycle of the alternating wave. This is the fundamental distinction between a half-wave rectifier and a full wave rectifier.
The full wave rectifier can be used to compensate for a half wave rectifier's lower efficiency.
Full wave rectification is the procedure used in a full wave rectifier to convert an AC signal to a voltage signal.
Full Wave Rectifier Circuit
Compared to half-wave rectifiers, these rectifiers have a few key advantages. The output of this rectifier has much less ripple than the output of the half-wave rectifier, resulting in a smoother output waveform. The average (DC) output voltage is higher than for the half-wave rectifier.
Full Wave Rectifier Theory
Two diodes are used in this circuit, one for each half of the wave. The secondary winding of a multiple-winding transformer is divided equitably into two halves with a common center-tapped connection. When a diode's anode terminal is positive relative to the transformer's center point C, the configuration causes each diode to conduct in turn, producing an output during each half-cycle. Compared to a half-wave rectifier, this rectifier has more flexible advantages
Working Principle of Full Wave Rectifier
The Full Wave Rectifier functions in accordance with the following:
- The full wave rectifier receives a very high input AC voltage.
- The full wave rectifier circuit's step-down transformer transforms high voltage AC into low voltage.
- The secondary transformer winding and the load resistor are both connected to the anode of the center-tapped diodes.
- The top half of the secondary winding, or terminal 1, will become positive during the AC's positive half cycle.
- While the center tap will have zero potential and terminal two, or the second half of the winding, will turn negative,
- During the positive half cycle, the diode D1 is forward biased and the diode D2 is reverse biased. This is due to the fact that it is attached to the secondary winding's bottom.
- As a result, D1 will permit current flow while D2 will obstruct it.
- The diode D1 is reverse biased and the diode D2 is forward biased in the case of a negative half cycle.
- This is due to the secondary circuit's top half turning negative and its bottom half turning positive.
- As a result, DC voltage is produced in a full wave rectifier for both the positive and negative half cycles.
Types of Full Wave Rectifier
These come in two varieties: bridge rectifier circuit and center tapped full wave rectifier. Full-wave rectifiers are used in a variety of applications because each type has unique features.
- Center Tap Full Wave Rectifier
- Full-Wave Bridge Rectifier
Center Tap Full Wave Rectifier
A secondary winding of a tapped transformer with the secondary winding of AB tapped at the center point "C" and two diodes such as D1, D2 connected in the upper and lower portions of the circuit can be used to construct this type of rectifier. The D1 diode uses the AC voltage that appears across the upper side of the secondary winding for signal rectification, while the D2 diode uses the lower of the two windings. This kind of rectifier is extensively used in thermionic valves & vacuum tubes.
The circuit for a center tap full-wave rectifier is displayed below. Once the AC supply is turned on, the circuit allows the AC voltage like Vin to flow across the two terminals like AB of the transformer's secondary winding.
Full-wave Bridge Rectifier Circuit
Four rectifying diodes can be used to create a full-wave rectifier for a bridge rectifier. There is no center tapping involved. As its name implies, a bridge circuit is a part of the circuit. Four diodes can be connected in the circuit in a closed-loop bridge configuration. Because there is no center-tapped transformer in this rectifier, it is less expensive and smaller.
Advantages of Full Wave Rectifier
- Full wave rectifiers have a rectification efficiency that is twice as high as half wave rectifiers. Half wave rectifiers have a rectification efficiency of 40.6%, while full wave rectifiers have an efficiency of 81.2%.
- Since full wave rectifiers have a low ripple factor, only a basic filter is needed. In a full wave rectifier, the ripple factor is 0.482, while in a half wave rectifier, it is roughly 1.21.
- Full wave rectifiers produce output voltage and power that are higher than what half wave rectifiers can.
- The full wave rectifier's only drawback is that it is more expensive and requires more circuit components than the half wave rectifier.
Applications of Full Wave Rectifier
The applications of a full-wave rectifier include –
- It is employed to determine the radio signal's modulating amplitude.
- Electric welding uses full wave rectifiers, and bridge rectifiers can supply polarized DC voltage.
- Due to its ability to transform voltage from high AC to low DC, the bridge rectifier circuit is employed.
- For devices like LEDs and motors that operate on DC voltage, they supply the power supply.