What is a Rectifier?
A rectifier is an electrical device that converts AC to the DC current. A mobile phone can only be charged expeditiously if a constant, consecutive voltage supply is being provided to it. When the charger is connected to the mainline, the AC input supplied to it is 220 V, and this supply when passed through the charger, we achieve the output of 5V DC. This is possible by using a rectifier in the circuit of the phone charger.
Here the voltage drop occurs by the transformer, and the conversion of AC to DC occurs by the device known as a rectifier.
Introduction
Rectifiers are used in not just a single device but have a variety of uses in various devices. This is used to modify the network systems. They are categorized based on the factors such as type, bridge configuration, and the components that are used in it. The rectifiers use the P-N junction type of diodes that help in converting the alternating current to direct current. To understand the Uses of Rectifier - Types and Their Uses and Functions, all the important information is provided via Vedantu that helps the students understand the concepts while also explaining how to apply them in real-life situations.
On this page, we’ll learn about the following:
Application of rectifier
Full-wave rectifier applications
Rectifiers are used to convert
Uses of the half-wave rectifier
Uses of full-wave rectifier
What is a rectifier?
Types of rectifier
Rectifier function
Full-wave bridge rectifier
Rectifier Function
A rectifier uses a P-N junction diode to convert AC to pulsating DC. This P-N junction diode allows the flow of an electric current in a forward-biased condition and blocks the electric current in a reverse-biased condition. In simple words, a P-N junction diode allows a unidirectional flow of current. This unique attribute of the diode allows it to act like a Rectifier. The below fig shows an output waveform for the basic rectifier.
Types of Rectifier
Half-wave Rectifier: In such a rectifier, the input voltage is described by a sinusoidal wave for a positive half-cycle.
Full-Wave Rectifier
Full-wave centre-tapped rectifier
Full-wave bridge rectifier
Half-Wave Rectifier
A type of electrical device that converts an AC voltage into DC voltage. Such a rectifier allows only one half-cycle of an AC voltage waveform by clipping the other half-cycle. These devices require only a single diode to construct. The advantage of the fact of using a diode is that it allows the unidirectional flow of current.
Fig.1 shows the functioning of the half-wave rectifiers, putting an AC waveform with positive and negative cycles as input power and after rectification, we obtain the DC output power with no negative cycle.
Rectifier efficiency is given by,
Where ηmax = 40.6 % (low)
Rectifier efficiency η is defined as the ratio of DC power (Pdc) to the applied input AC power (Pac) where ηmax has a very low value.
Uses of a Half-wave Rectifier
There are various uses of a half-wave rectifier, some of which are stated below.
Used in
Low power simple battery charger circuit.
Pulse Generator Circuits.
Signal demodulation circuits.
Firing circuits.
Soldering Iron circuit.
Amplitude Modulation (AM) Radio circuits as a Detector.
Full-Wave Rectifier
A Full wave Rectifier is a circuit that changes an alternating current voltage into a pulsating dc voltage using both half cycles of the applied ac voltage supply.
It utilizes two diodes of which one conducts during one-half cycle while the other diode remains off and conducts during the other half cycle of the applied ac voltage. Hence in such a device, We obtain the positive and negative output cycle however one diode stops the current flow the other diode conducts and allows the current.
In this device, for both the input AC signals either positive or negative, the output DC is generated.
Full-Wave Bridge Rectifier
A Full wave bridge rectifier is a circuit organization that makes use of both half cycles of input AC and converts them to DC. There are 4 diodes (D1, D2, D3, D4) arranged as a bridge. Therefore, this arrangement is known as a Bridge Rectifier
The Positive Half-cycle
During the positive half-cycle, diodes D2 and D4 are forward-biased starts conducting diodes D1 and D3 are reverse-biased as an open circuit. Thus, current (i) flows through the load resistor RL.
The Negative Half-cycle
During the negative half-cycle, the diodes D3 and D4 are forward biased while D1 and D2 remain switched off. The current flow through the load is in the direction as before.
Applications of a Full-wave Bridge Rectifier
Full Wave Bridge Rectifiers are mostly used for the low cost of diodes because of being lightweight and highly efficient.
The important uses of the full-wave bridge rectifier are given below.
Mobile phones, laptops, charger circuits.
Uninterruptible Power Supply (UPS) circuits to convert AC to DC.
Our home inverters convert AC to DC.
LCD, LED TVs.
Car Alternator to charge the batteries during the running of the car.
LED Driver Circuits
Audio Amplifier
Radios
The Need for Rectifiers
There are two types of voltages that are observed widely and are classified into either alternating voltage or direct voltage. These voltages can easily be interconverted based on the circuit that has been used. For example, the main supply for homes needs only a small amount of DC voltage while the main grid only provides alternating voltage. Due to this, it is needed to convert the AC into DC which can be easily done with the help of rectifiers being used in the circuit.
It can also be perceived in another way where there is the interconversion of current taking place with the help of a rectifier. The alternating current is being converted to direct current which most of the appliances in a home will require. It is also seen that these rectifiers take in both the positive and negative components of the current and convert it to one with only positive components.
FAQs on Uses of Rectifier
1. What are the Advantages of using the Bridge Rectifiers?
The advantages of rectifiers that are used in circuits can be provided as follows:
The rectification efficiency that is seen in a bridge rectifier will be double that of the half-wave rectifier.
It is seen that in a bridge rectifier, the simple filtering circuit is used as it provides low ripple voltage output.
The transformer utilization factor is quite high for bridge rectifiers.
It has four diodes that help in rectifying the negative current that might have been otherwise impossible in half-wave rectifiers.
2. What are uncontrolled Rectifiers and what are their types?
These are the sort of rectifiers whose voltage output cannot be controlled and are hence said to be uncontrolled rectifiers. A rectifier needs a switch to work well and these switches can be classified based on their types into either controllable switches or uncontrollable switches. A diode is said to be a diode that works in only a single direction. The working of the diode is hence not controlled and it will keep on conducting current as long as it is forward biased. Due to this configuration of the diode, it is seen that the rectifier is not completely in the control of the user hence providing the name uncontrolled rectifiers.
3. What is a bridge Rectifier and how does it work?
One of the types of a full-wave rectifier is the bridge rectifier which uses four diodes that helps in the conversion of both half cycles of AC into DC output. In comparison to a half-wave rectifier, the full-bridge rectifiers consist of an additional branch that helps it to conduct for the negative half of the voltage waveform. Hence it is seen that the average voltage at the output of the full-bridge rectifier will have double the value of the half-bridge rectifier.
4. What are single-phase and three-phase Rectifiers?
This type of classification is entirely dependent on the type of input a rectifier works on. It is quite evident through the name that when the input is in a single phase it will be called a single-phase rectifier however if the input has three phases then the rectifier will be called a three-phase rectifier. The single-phase rectifier will consist of four diodes while the three-phase rectifier will consist of a total of six diodes that have been arranged in such a way that the output is obtained as desired. Depending on the type of switch that has been used these can either be uncontrollable rectifiers or uncontrollable rectifiers. To learn more about the rectifiers and its type students can use the Vedantu NCERT Solutions for Physics.
5. What are the limitations of Rectifiers and why is it important to study Rectifiers?
While there are a lot of advantages to the uses of rectifiers it is seen that these come with certain limitations and can be provided as follows:
Although rectifiers have a full-wave property they produce a continuous output voltage or current in one direction where the rectified voltage will be present in the form of half sinusoidal pulses.
The output voltage is available only in a single direction but is not constant.
Such a pulsating output will have some sort of alternating current voltage ripple that has been mixed in with a direct current voltage and hence it is necessary to filter out the alternating current ripple using an additional filter configuration to get a result of direct current voltage output.
6. What are Rectifiers and their types?
A rectifier is an electrical device consisting of one or more diodes that allow the unidirectional flow of current. It basically converts AC into DC.
The rectifiers are categorized into three types namely uncontrolled, half controlled, and full controlled rectifiers.
7. Why are half-wave Rectifiers not used in dc power supply?
The half-wave rectifier is used most commonly in low-power applications because the output amplitude is less than the input amplitude and there is no output during the negative half-cycle.
