Types of Rectifier Overview
Rectifier circuits are the most common in electronics because nearly all electronic devices run on DC (Direct Current), but the availability of the DC There are few sources, such as the alternating current (AC) that comes from the electrical outlets in our homes. In order to convert AC into DC, the rectifier is the best candidate for use in both industries and homes. Rectifiers are used by even our cell phone chargers to convert the AC from our home outlets to DC. There are many different types of rectifiers, each with a specific use. There are currently primarily two voltage types that are frequently used. The voltage types are alternating and direct. Using unique circuits created for that conversion, these voltage types can be changed from one type to another.
What is Rectifier?
Alternating current is changed into direct current by a rectifier. DC voltage is the foundation for the operation of many electrical circuits. A device that quickly transforms AC voltage or current into DC voltage or current is a p-n junction diode. A rectifier can be defined as:
"An electrical device that allows current to flow through it only in one direction, converting alternating current into direct current."
There are many different physical forms of rectifiers, including:
- Solid-state diodes
- Vacuum tube diodes
- Mercury-arc valves
- Silicon-controlled rectifiers, and more.
A p-n junction diode allows electric current to flow when biased forward, but blocks it when biased backward. Simply put, a diode allows only one direction of electric current to pass. The diode's special property enables it to work as a rectifier.
Since current can only flow in one direction, a diode acts as a one-way valve. This is referred to as the correction. Rectifiers can be classified under different waveforms, like:
- Half-Wave Rectifier
- Full-Wave Rectifier
- Single-Phase AC
- Three-Phase AC
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Different Types of Rectifiers
Rectifiers can be divided into a number of different designs depending on the type of supply, bridge configuration, components used, type of control, etc. These are primarily divided into two categories: single-phase rectifiers and three-phase rectifiers. The three types of rectifiers—uncontrolled, partially controlled, and fully controlled—are further classified under the heading of rectifiers. Let's take a quick look at a few of these rectifier types. Rectifiers are classified into two types:
Uncontrolled Rectifiers |
Controlled Rectifiers |
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Half Wave Rectifiers |
Full Wave Rectifiers |
Half Wave Rectifiers |
Full Wave Rectifiers |
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Positive Half Wave Negative Half Wave Positive Half Cycle Negative Half Cycle |
Bridge Rectifier Center Tap Full-wave |
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Controlled Bridge Controlled Center Tap
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1. Uncontrolled Rectifier
Uncontrolled rectifier refers to a rectifier whose output voltage cannot be controlled. Switches are used in rectifiers, and they come in both controllable and uncontrollable varieties. A diode is a two-terminal component that has only one direction in which current can flow, making it a unidirectional device. Because it can only function if it is connected in a forward biased manner, this device cannot be controlled.
When a diode is connected to a rectifier in any way, the rectifier cannot be fully controlled by an operator and is referred to as an uncontrolled rectifier. It forbids changing the power in accordance with the demands of the load. Therefore, this type of rectifier is typically used in stationary or reliable power supplies. This type of rectifier only makes use of diodes and generates stable output voltage using AC as its sole input.
Uncontrolled rectifiers are further divided into two categories:
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Half Wave Rectifier |
Full Wave Rectifier |
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When an AC supply is applied at the input to this kind of rectifier, only the positive half of the cycle becomes visible across the load, while the negative half is hidden. It requires one diode for a single-phase supply and three diodes for a three-phase supply. Only half of the i/p waveforms reach the output, making it incapable. More filtering is needed in the half-wave rectifier circuit in order to lessen the ripples of the AC frequency coming from the o/p. |
When an AC supply is applied to the i/p during both half cycles of this type of rectifier, the current flowing through the load moves in the same direction. Because both polarities of the i/p waveform are changed to pulsating DC in this circuit, a higher standard output voltage is produced. This type of rectification can be accomplished by using no more than two crystal diodes with different current conductivities. A circuit with more than one diode is used to create a full-wave rectifier. These rectifiers fall into one of two categories: |
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Types of Half Wave Rectifier |
Types of Full Wave Rectifier |
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Positive Half- wave Rectifier: Positive half wave rectifiers are those that only alter the positive half cycle while blocking the negative half cycle. |
Bridge Rectifier: Four diodes can be used to create a bridge rectifier circuit, which converts the input AC half-cycle to the output DC. Therefore, the four diodes are primarily connected in an exact form in this type of rectifier. The two diodes D1 and D2 become forward biased during the positive half cycle of the bridge rectifier, while D3 and D4 become reverse biased. |
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Negative Half- wave Rectifier: A negative half-wave rectifier is one that merely converts the negative half cycle of an AC signal into a DC signal. A half-wave rectifier is the simplest type of rectifier when compared to all other types because it only uses one diode in its construction. |
Center Tap Full-wave Rectifier: A transformer with a secondary winding that is tapped at the center point is used in this kind of rectifier circuit. Each diode in the circuit is connected so that it receives a half-cycle of the input AC voltage. While the other diode uses the lower half of the secondary winding for rectification, one diode uses the ac voltage visible on the upper half of the secondary winding. |
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Positive Half Cycle: Forward bias is the tendency of a diode's anode terminal to become positive during the positive half cycle while the cathode terminal remains negative. It will enable the positive cycle to continue its supply. |
Full Wave Bridge Rectifier: One of the effective designs for a full-wave rectifier that makes use of four diodes in a bridge topology is the bridge rectifier circuit. A standard transformer is used in place of the center tap transformer. The load resistor is connected across the remaining two diagonally different ends of the bridge, and the AC supply that needs to be rectified is applied to the bridge's diagonally different ends. |
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Negative Half Cycle: Reverse bias refers to the diode's anode terminal turning negative during the negative half cycle while the cathode terminal turns positive. The diode will thus stop the negative cycle. |
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2. Controlled Rectifier
A rectifier is referred to as a controlled rectifier when its output voltage varies or changes. Once we examine the shortcomings of an uncontrolled bridge rectifier, the necessity for a controlled rectifier becomes evident. The conversion of an uncontrolled rectifier to a controlled rectifier uses current-controlled components like SCRs, IGBTs, and MOSFETs.
We will have total control once SCRs are turned ON/OFF based on the applied gate signals. In general, these are preferred more so than their uncontrolled counterparts. A thyristor is another name for a silicon-controlled rectifier (SCR). It is a three-terminal diode, with anode, cathode, and gate as its terminals.
Half Wave Rectifier |
Full Wave Rectifier |
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One silicon controlled rectifier (SCR) can be used to create the half-wave controller rectifier. The half-wave controlled rectifier has a similar design to a half-wave uncontrolled rectifier, with the exception that we change the diode using an SCR. A silicon-controlled rectifier cannot operate in reverse bias, so it will block the negative half cycle. Throughout the positive half cycle, the SCR will conduct current on only one condition once a pulse is given to the input of the gate terminal, like a periodic pulse signal. |
A full-wave controlled rectifier is one that converts both the positive and negative half cycles of the AC into DC while controlling the o/p amplitude. A controlled full-wave rectifier can be divided into two types, such as controlled bridge and controlled center tapped, similar to an uncontrolled rectifier. |
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Types of Half Wave Rectifier |
Types of Full Wave Rectifier |
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Controlled Bridge Rectifier: An SCR bridge can replace the diode bridge in a controlled bridge rectifier using a setup akin to the bridge rectifier. |
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Controlled Center-Tap Rectifier: The controlled center tap rectifier design primarily uses two SCR in place of the two diodes, similar to the center-tap uncontrolled rectifier. Depending on the i/p AC frequency, these SCRs will switch at various times. |
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Single Phase & Three Types of Rectifiers
A rectifier can be categorized based on how a particular input type operates. A rectifier is referred to as a single-phase rectifier once it has a single-phase input. Similar to this, a rectifier is referred to as a 3-phase rectifier if the input is three-phase. Four diodes can be used to design a single-phase bridge rectifier, while six diodes, arranged in a specific pattern to produce the desired output, can be used to design a three-phase rectifier.
Based on the switching elements used in every type of rectifier, such as thyristors, diodes, etc., these rectifiers are classified as controlled or uncontrolled rectifiers.
Comparison of Different Types of Rectifiers
The comparisons between different types of rectifiers on the various points are tabulated below.
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Properties |
Half wave rectifier |
Full-wave center-tap rectifier |
Full-wave bridge rectifier |
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Number of Diodes |
1 |
2 |
4 |
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D.C Current |
Im / π |
2 Im / π |
2 Im / π |
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Transformer Necessary |
No |
Yes |
No |
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Max Value of Current |
Vm / (rf + RL) |
Vm / (rf + RL) |
Vm / (2rf + RL) |
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Ripple Factor |
1.21 |
0.482 |
0.482 |
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O/p Frequency |
fin |
2 fin |
2 fin |
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Max Efficiency |
40.6% |
81.2% |
81.2% |
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peak inverse voltage |
Vm |
2 Vm |
2 Vm |
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Working of Half-wave Rectifier
An AC voltage waveform's first half-cycle can pass through a half-wave rectifier, but the second half-cycle cannot.
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Construction of Half-wave Rectifier |
Working Principle of Half-wave Rectifier |
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The components of a half-wave rectifier are as follows-
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The half-wave rectifier's operating principle is-
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Working of Full-wave Rectifier
A full-wave rectifier produces pulsating direct current by converting an entire cycle of alternating current.
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Construction of Full-wave Rectifier |
Working Principle of Full-wave Rectifier |
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A full-wave rectifier is built as follows-
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The full-wave rectifier's operating principle is-
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Limitations of Rectifier
There are some limitations with rectifiers. Some of them include:
- Full-wave rectifiers produce continuous voltage/current in one direction, but the rectified voltage is generated as half-sinusoidal pulses.
- The output voltage is unidirectional but changes.
- In order to produce pure DC voltage output from a pulsating output with some AC ripple mixed in, we must filter out the AC ripple using an additional filter configuration.
Applications of Rectifier
Rectifiers are used in a number of applications, such as:
- For electric welding, rectifiers are used to supply polarized voltage.
- Half-wave rectifiers have a repellent effect on mosquitoes.
- Half-wave rectifiers are used as signal peak detectors in AM radio.
- Rectifiers are used in voltage multipliers, modulation, and demodulation.
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Things to Remember
- To power electronic circuits, rectifiers convert an AC input voltage into a DC voltage supply.
- By allowing current to flow only in one direction, rectification is the process of changing alternating current (AC) into direct current (DC).
- A junction diode has a low resistance to current flowing in one direction when it is forward biased and a high resistance when it is reverse biased.
- An indicator of a rectifier's effectiveness is the ripple factor.
- A type of rectifier known as a half-wave rectifier is one that only changes the first half of an alternating current cycle into direct current.
- The positive and negative halves of the AC waveform are converted by a full-wave rectifier.