Full wave rectifier: The working, types and advantages

PCBWay

The conversion of alternating current into direct current is known as rectification. This can be done using either a single or several diodes. A diode used for rectification is known as a rectifier.

DRex Electronics

There are two types of rectifiers:

  1. Half-wave Rectifier
  2. Full-wave Rectifier

In half-wave rectification circuits, a single diode converts alternating current to direct current. This makes it straightforward to design for rectification.

However, it has one drawback: it converts only half of the alternating current wave to direct current. As a result, this circuitry suffers from greater power losses. This rectifier is likewise not suitable for applications that require pure direct current.

To achieve full-wave rectification, a full-wave rectifier was introduced, which uses more than one diode to convert the entire AC waveform into direct current.

In this post, we will look at the working, types, advantages, and applications of a full wave rectifier.

Full-wave rectifier circuit

There are two ways to build a full wave rectifier. The first approach employs two diodes and a center-tapped transformer. This configuration is referred to as a center-tapped full-wave rectifier.

Another technique employs a conventional transformer with four diodes configured as a bridge. This is referred to as a bridge rectifier.

The full wave rectifier circuit comprises two diodes which are linked and center-tapped and a step-down transformer. The output voltage is measured across the attached load resistor.

The Working of a Full Wave Rectifier

The input AC to the full wave rectifier is extremely high. The step-down transformer of the rectifier circuit converts alternating current (AC) of high-voltage to low-voltage AC. The load resistor is connected to the anode of the center-tapped diodes and also linked to the transformer’s secondary winding.

The top half of the secondary winding is positive and the second half is negative during the positive half cycle of the alternating current.

Due to its connection to the top of the secondary winding, diode D1 becomes forward-biased during the positive half cycle, but D2 diode becomes reverse-biased due to its connection to the bottom of the secondary winding. As a result, diode D1 will operate as a short circuit and diode D2 will not operate as it becomes an open circuit.

Because the top half of the secondary circuit becomes negative and the bottom half becomes positive during the negative half cycle, D2 diode is forward biased and diode D1 is reverse biased. Consequently, DC voltage is now produced for both the positive and negative half cycles in a full wave rectifier.

Types of Full Wave Rectifier

Depending on the recommended topology, the full-wave rectifier can be configured with at least two basic diodes or with up to four diodes.

The fundamental idea behind a diode, as is common knowledge, is that current can only travel in one direction while being blocked in the other. Numerous rectifiers are constructed with this principle as their foundation. This allows for the classification of full-wave rectifiers into two categories, namely:

(1) Center – Tapped

The components of a center-tapped full-wave rectifier circuit are a resistive load, a transformer, and two diodes.

(2) Full Wave Rectifier (Bridge)

In this type of rectifier, four diodes are connected diagonally in bridge topology to make up a full-wave bridge rectifying circuit.

Advantages of a Full Wave Rectifier

  • Full-wave rectifiers have double the rectification efficiency of half-wave rectifiers. Half-wave rectifiers have an efficiency of 40.6%, whereas full-wave rectifiers have a 81.2% rectification efficiency.
  • Compared to half-wave rectifiers, full-wave rectifiers yield higher output voltages and higher output powers. The DC value also attains a higher mean.
  • A basic filter is necessary since full wave rectifiers have a low ripple factor. The ripple factor in a half-wave rectifier is approximately 1.21, but in a full-wave rectifier it is 0.482.
  • As both cycles are employed in the rectification, the input voltage signal will not be lost.
  • Bridge rectifiers are more affordable than center-tapped full-wave rectifiers since the latter is more expensive.
  • Both of the cycles are used. As a result, the output power is not lost.

The full wave rectifier’s sole drawback is that it requires more circuit components than a half wave rectifier, which raises the price.

Applications

  • This circuit is recommended for using electricity to supply a constant DC voltage in a polarized manner.
  • The full-wave bridge rectifier circuit is used to detect the modulating radio signal’s amplitude.
  • These are utilized when powering up equipment such as LED devices and motors.
  • This rectifier circuit is a component of the power supply unit in many appliances because it has high rectification efficiency.
  • It can produce low DC values from high AC voltages.

These are only some of the benefits and uses of the full-wave rectifier circuit. This type of circuit has many other applications. When compared to half-wave rectifiers, these rectifiers are used more effectively. The rectifiers’ excellent efficiency is primarily responsible for their widespread use in a variety of power supply circuit applications.

In the world of power supplies, full-wave rectifiers are more advantageous than disadvantageous. The expensive nature of the center-tapped transformer used in this circuit is its lone drawback. To get around this drawback, a bridge rectifier circuit with four diodes coupled in a bridge topology is built.

FAQs: Frequently Asked Questions

 What is a full wave rectifier?

Full wave rectifiers produce pulsating DC by converting the polarities of an AC waveform.

What is the application of a full wave rectifier?

Full wave rectifier circuits are used in electric welding and signal modulation.

What is a center-tapped full wave rectifier?

A center-tapped full wave rectifier is a kind of rectifier that converts the entire AC signal into a DC signal using two diodes and a center-tapped transformer.

Why is a capacitor used in a circuit for a full wave rectifier?

A capacitor is used to lower the ripple factor in the circuit.

What drawbacks might full wave rectifiers have?

When a small amount of voltage needs to be rectified, full wave rectifiers are not the best option. This is because two diodes linked in series in a full wave circuit provide a double voltage drop because of internal resistances.