The process of converting the AC current into DC current is referred to as rectification. Rectification can be achieved by using a single diode or group of diodes. These diodes which convert the AC current into DC current are referred to as rectifiers. Rectifiers are generally classified into two types:
- Half wave rectifier
- Full wave rectifier
What Is Half Wave Rectifier?
A half wave rectifier is defined as a type of rectifier that only allows one half-cycle of an AC voltage waveform to pass, blocking the other half-cycle. Half-wave rectifiers are used to convert AC voltage to DC voltage and only require a single diode to construct. The working of half wave rectifier takes advantage of the fact that diodes only allow current to flow in one direction.
A single diode in half wave rectifier only allows either a positive half cycle or a negative half cycle of the input AC signal and the remaining half cycle of the input AC signal is blocked. As a result, a large amount of power is wasted. Moreover, half wave rectifiers are not suitable in the applications which require a steady and smooth DC voltage. Therefore, half wave rectifiers are not efficient AC to DC converters.
The half wave rectifier is made up of an AC source, transformer (step-down), diode, and resistor (load). The diode is placed between the transformer and resistor (load).
What You Need To Know About Half Wave Rectifier
- Half wave rectifier current only during positive half cycle of the applied input, therefore, it shows unidirectional characteristics.
- Output frequency (fundamental ripple frequency) of half wave rectifier is equal to the frequency of input i.e 50Hz.
- Half wave rectifier has less ripple factor when compared to full wave rectifier. For half wave rectifier it is about 1.21.
- The peak inverse voltage for half wave rectifier is equivalent to the maximum value of applied input voltage.
- Half wave rectifier has a fair good voltage regulation mechanism.
- Half wave rectifier circuit requires only one diode.
- Half wave rectifier has an efficiency of 40.6%.
- Half wave rectifier does not require center tapping of the secondary winding of transformer.
- DC saturation of the transformer core is a common problem in the half waver rectifier circuit.
- Half wave rectifier is less costly since it requires only one diode.
What Is Full Wave Rectifier?
A full wave rectifier is a type of rectifier which converts both half cycles of the AC signal into pulsating DC signal. The average value of the output is higher in full-wave rectifier compared to that of half-wave rectifier. The numbers of ripples in the full-wave rectifier circuit are less in number producing the smoothest output.
To construct a full wave circuit, two diodes are required. Each diode is utilized during each cycle. When the positive cycle is applied, one diode conducts and during a negative cycle, the other diode tends to conduct. In this way, rectification is possible for a full-wave rectifier. Because of both the cycle’s utilization, there is no loss in power.
What You Need To Know About Full Wave Rectifier
- Full wave rectifier, both the halves of the input signal is utilized at the same time of operation, therefore it shows bidirectional characteristics.
- Full wave rectifier output frequency (fundamental ripple frequency) is twice that of the applied input i.e 100Hz.
- Full wave rectifier has more ripple factor when compared to half wave rectifier. For full wave rectifier, it is about 0.482.
- Peak inverse voltage for full wave rectifier is twice the maximum value of applied input voltage.
- Full wave rectifier has a better voltage regulation mechanism when compared to half wave rectifier.
- In full wave rectifier circuit, two or even 4 diodes are used in the circuit.
- Efficiency of full wave rectifier is 81.2%.
- Full wave rectifier requires center tapping of the secondary winding of the transformer.
- Full wave rectifier circuit does not have DC saturation of transformer core because the current in the secondary winding flows in two halves of the secondary winding of the transformer and in opposite direction.
- Full wave rectifier is more costly since it requires more than 1diodes.
Also Read: Difference Between Step-Up And Step-down Transformer
Difference Between Half Wave And Full Wave Rectifier In Tabular Form
BASIS OF COMPARISON | HALF WAVE | FULL WAVE |
Description | Half wave rectifier current only during positive half cycle of the applied input, therefore, it shows unidirectional characteristics. | Full wave rectifier, both the halves of the input signal is utilized at the same time of operation, therefore it shows bidirectional characteristics. |
Fundamental Ripple Frequency | Output frequency (fundamental ripple frequency) of half wave rectifier is equal to the frequency of input i.e 50Hz. | Full wave rectifier output frequency (fundamental ripple frequency) is twice that of the applied input i.e 100Hz. |
Ripple Factor | Half wave rectifier has less ripple factor when compared to full wave rectifier. For half wave rectifier it is about 1.21. | Full wave rectifier has more ripple factor when compared to half wave rectifier. For full wave rectifier, it is about 0.482. |
Peak Inverse Voltage | The peak inverse voltage for half wave rectifier is equivalent to the maximum value of applied input voltage. | Peak inverse voltage for full wave rectifier is twice the maximum value of applied input voltage. |
Voltage Regulation | Half wave rectifier has a fair good voltage regulation mechanism. | Full wave rectifier has a better voltage regulation mechanism when compared to half wave rectifier. |
Number Of Diodes | Half wave rectifier circuit requires only one diode. | In full wave rectifier circuit, two or even 4 diodes are used in the circuit. |
Efficiency | Half wave rectifier has an efficiency of 40.6%. | Efficiency of full wave rectifier is 81.2%. |
Center Tapping | Half wave rectifier does not require center tapping of the secondary winding of transformer. | Full wave rectifier requires center tapping of the secondary winding of the transformer. |
DC Saturation | DC saturation of the transformer core is a common problem in the half waver rectifier circuit. | Full wave rectifier circuit does not have DC saturation of transformer core because the current in the secondary winding flows in two halves of the secondary winding of the transformer and in opposite direction. |
Cost | Half wave rectifier is less costly since it requires only one diode. | Full wave rectifier is more costly since it requires more than 1diodes. |
Also Read: Difference Between Center Tapped And Bridge Rectifier
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