Difference Between Diode and Rectifier

Switching Diode vs Rectifier Diode

Switching diodes are also known as pulse diodes. They are used in discrete systems and act as critical devices in transmitting pulses in the forwarding direction. Rectifier diodes are redesigned to serve the purpose of rectifying alternating current. The rectifier diode is designed for rectifying alternating current. The Schottky barrier is a variant of the rectifier diode and is particularly popular in the field of digital electronics. Basically, in Switching diodes vs Rectifier diodes, the connections remain the same. It is just the applications that differ. A stable voltage drop is generated that gives a stable voltage when current is flowing. Diodes have specialized switching operations. 


What is a Diode?

A diode is a semiconductor device which allows an on way switch for current. It will enable the flow of current in one direction and restricts the movement in other opposite directions. Diodes are also known as rectifiers as they change the alternating form of current into direct current. Every diode has an anode and a cathode that allows current to flow only when a positive voltage is applied to the positive lead that is the anode. Every diode is forward biased when it allows current to flow. A reverse-biased diode acts as an insulator. Diodes are used as signal limiters, voltage regulators, switches, signals, and even oscillators. 


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What is a Rectifier?

Rectifiers are used for converting AC into DC. There are two types of rectifiers used nowadays. One of the most common rectifiers in the bridge rectifier. It supplies electric power and involves DC-DC conversion. The other different types of rectifiers are: 

  • Single-phase rectifiers

  • Three-phase rectifiers 

  • Half-wave rectifiers 

  • Full-wave rectifiers 

  • Controlled rectifiers

  • Uncontrolled rectifiers

  • Centre tapped rectifiers


What are the Differences Between Diode and Rectifier?

A diode is a switching device, while a rectifier is generally used for the conversion of AC voltage to DC voltage. There are some more differences between the two, such as: 

  1. A diode allows the flow of current only when it is forward biased. The diode blocks the reverse flow of current. A rectifier, on the other hand, consists of a transformer, a diode, and a filter circuit. All of these collectively convert AC to DC. 

  2. In diodes, the current-carrying capacity is low, while the position in rectifiers is high. 

  3. The different types of diodes are Zener diodes, photodiodes, and more. Rectifiers are of two kinds: single-phase rectifiers and three-phase rectifiers. A further division of single-phase rectifiers is full-wave rectifiers and half-wave rectifiers. 

  4. Rectifiers are used in a computer system, while diodes are used in switches and clippers. 

  5. Diodes were initially known as valves. They are made up of germanium or silicon most of the time. 


Solved Examples

Explain forward biasing and reverse biasing? 


Forward Biasing: When the outer end of the reverse type section is connected to the negative terminal, and that of the p-type section is connected to the positive terminal, the biasing of the junction is called forward bias.


The free majority charge carriers from each part move forward towards the junction. If forward bias potential is more than a potential barrier, the charges from both sections cross the intersection, and a current flows through the intersection and the circuit. It is called forward current. The size of the depletion layer decreases in forward biasing, and hence resistance decreases.


Reverse Biasing: When the outer end of the re-type section is connected to the positive terminal and that of the p-type section is connected to the negative terminal, the biasing of the junction is called reverse biasing.


The minority carrier charge is made to move toward the junction due to reverse bias. The minority carrier charge crosses the intersection, and there is minimal current order to micron across the intersection - the size of the depletion layer increases in reverse bias, and hence resistance increases. 


Fun Fact About Diodes and Rectifiers

  • Current flows only in one direction in a diode. 

  • In 1938 the concept of Schottky diode was first discovered. 

  • Diodes are used in solar cells and also radar detectors. 

  • Photodiodes and Zener diodes are beneficial electronic components. Zener diodes are used as voltage regulators. 

  • All diodes are rectifiers, but all rectifiers are not diodes. 

  • Every diode has a black band signifying the cathode. 

  • Silicon diodes are popularly used in the market and require 0.5 volts for current to pass.

FAQ (Frequently Asked Questions)

1. What are Special - Purpose Diodes and Their Applications?

Ans: There are some particular purpose diodes that serve few specific functions. There are many such particular purpose diodes like the transient voltage suppression diodes, hold diodes, super barrier diodes and point contact diodes. A junction has two potentials on either side. There exists a capacitance in the depletion region. The tunnel diode has an increased concentration in the PN junction. The concentration increases with an increase in energy. The varactor diode and tunnel diode have some applications such as:

  • Frequency modulator 

  • Phase shifter 

  • Automatic frequency control 

  • Tank circuit 

  • Microwave oscillators 

  • Relaxation oscillators 

  • High-speed switching devices, along with memory storage devices.

2. Where are Diodes Used in Home Applications?

Ans: Diodes are present in basically every home appliance such as phones, LED, laptops, TV’s, play stations and any other electronic device. Every device has an AC DC converter. If you unscrew your devices, then the resistor, capacitors and inductors are easily visible. Electronic circuits like remote toys have two parts. One is a small p-type semiconductor which is grey. The other is a black coloured n-type semiconductor. Diodes are mostly electronic devices which protect the home appliances such as lights and remote controls in televisions and radio players. While connections the diode make sure not to mix up the connections. Current will not flow if the connections are not proper.