Uses of Rectifier - Applications, Principal, FAQs

What is a Rectifier ?

A rectifier changes the back-and-forth flow of AC into the one-direction flow of DC. This is important because many electronic devices (like mobile chargers, radios, and TVs) work only on DC.

A rectifier is analogous to a one-way valve that permits an electrical current to flow in just one direction. The symbol of Rectifier is shown in fig1.0

What is Rectification ?

The process of converting AC power into DC power is called rectification.
In AC, current changes direction periodically, whereas DC flows only in one direction. Rectification converts this bidirectional flow into a unidirectional flow.

The method of converting AC current to DC current is understood as rectification. Rectification is the process of transforming bidirectional current flow to unidirectional current flow. The method is of important importance in many areas of circuit design, including radio communication and AC to DC power conversion.

Rectifiers are widely used in:

• Power supplies
• Battery charging circuits
• Radio communication
• Electronic devices
• Motor drives
• Control systems

There are mainly three types of rectifiers:

1. Half-Wave Rectifier
2. Full-Wave Rectifier
3. Bridge Rectifier

Types of Rectifiers

1. Half-Wave Rectifier

• Converts only one half of the AC input (either positive or negative).
• Simple but inefficient because half of the input is wasted.

2. Full-Wave Rectifier

• Converts both halves of the AC input.
• Gives more output and is more efficient than half-wave rectifier.

3. Bridge Rectifier

• Uses four diodes arranged in a bridge structure.
• Converts entire AC waveform into DC .
• Most commonly used because it provides higher efficiency and works without a center-tapped transformer.

Applications and Uses of Rectifier

Rectifiers are extremely important because almost all electronic devices operate on DC power.
1. Powering Electrical Appliances
Every modern device - phones, laptops, LED TVs, routers, music systems - uses a rectifier inside its power adapter to convert AC to DC .
2. Used with Transformers
Half-wave or full-wave rectifiers are used with step-up or step-down transformers to obtain the required DC voltage.
3. Soldering and Welding

• Half-wave rectifiers are used in soldering tools and mosquito repellents.
• Bridge rectifiers are used in arc welding machines to supply stable DC current.

4. Radio and Communication Systems
Half-wave rectifiers work as detectors in AM radio to extract audio signals.

5. Pulse and Firing Circuits
Rectifiers help generate pulses in timing circuits and triggering systems.

6. Modulation and Demodulation
Full-wave rectifiers are used to demodulate AM signals in communication circuits.

7. Voltage Multipliers
Rectifiers are used in circuits that need high DC voltage from small AC input.

Also Read:

• NCERT Solutions for Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and
  Simple Circuits
• NCERT Exemplar Class 12 Physics Solutions Chapter 14 Semiconductor Electronics: Materials, Devices and
  Simple Circuits
• NCERT notes Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple
  Circuits

Principal of Rectifier

Rectifier converts AC → DC.
A rectifier will produce a wave that's unidirectional, like:
Half-Wave Rectifier Without Smoothing Capacitor:

Half-Wave Rectifier without Smoothing Capacitor:

Full-Wave Rectifier with Smoothing Capacitor:

Fully rectified without ripple:

Rectifiers use diodes to form the present only pass in one direction (Diode has this feature, allowing current to flow only in one direction).
Capacitors are used with diodes to assist in smoothing and converting the pulsating DC to somehow steady DC with a coffee ripple.
A very simple Half-Wave diode without smoothing capacitor:

In the +ve cycle of the AC, the diode conducts and therefore the output is that the same because the input.
In the -ve cycle of the AC, the diode doesn't conduct then the voltage is zero across the load resistor, and since there's no current flowing then V=RL×0=0.
The half-wave rectifier actually may be a simple one. There are other types that attempt to maintain the clipped part (full-wave).

Examples:

The best example of rectifier that's utilized in our lifestyle is within the mobile charger. A mobile can only be charged efficiently if a continuing, uninterrupted voltage supply is being provided thereto .This can be done employing a rectifier within the circuit of the phone charger.
Here is that the phone charging circuit, which is essentially an AC to DC convertor.

The bridge like circuit you see within the diagram at the input side is that the ‘bridge rectifier’ used for the aim.
Thus, during this way rectifier are often utilized in any application where AC input has got to be converted to DC.

Also check-

• NCERT Exemplar Class 11th Physics Solutions
• NCERT Exemplar Class 12th Physics Solutions
• NCERT Exemplar Solutions for All Subjects

NCERT Physics Notes:

• NCERT Notes Class 11th Physics
• NCERT Notes Class 12th Physics
• NCERT Notes For All Subjects