Switching Diode vs Rectifier Diode with explanation
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 the current is flowing. Diodes have specialized switching operations.
What is a Diode?
A diode is a semiconductor device that allows an on way switch for current. It will enable the flow of current in one direction and restrict 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 is 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
Controlled and Uncontrolled Rectifiers
Rectifiers are classified into many designs based on criteria such as power supply type, bridge layout, components used, control nature, and so on. These are primarily divided into two types: single-phase and three-phase rectifiers. Rectifiers are further categorised into three types: uncontrolled, half-controlled, and fully regulated rectifiers. Let us look at some of these rectifiers in more detail. Uncontrolled rectifiers and controlled rectifiers are the two types of rectifiers.
Uncontrolled Rectifiers
An uncontrolled rectifier is a rectifier whose output voltage cannot be controlled. A rectifier operates with switches, which come in both controllable and uncontrollable varieties. A two-terminal component, such as a diode, is a unidirectional device whose primary function is to enable current to flow in only one way. This device cannot be operated since it will only function if it is connected in a forward-biased configuration.
When a diode is coupled to a rectifier in any configuration, the rectifier cannot be totally controlled by an operator and is referred to as an uncontrolled rectifier. It does not allow the power to adjust depending on the load requirements. As a result, this type of rectifier is typically used in fixed or stable power supplies. This type of rectifier is made up entirely of diodes and offers a consistent output voltage depending solely on an alternating current input.
Controlled Rectifiers
A controlled rectifier is one in which the output voltage of a rectifier changes or varies. When we look at the defects of an uncontrolled bridge rectifier, we can see why we need a regulated rectifier. Current-controlled devices such as SCRs, IGBTs, and MOSFETs are used to convert an uncontrolled rectifier to a controlled rectifier.
We shall have perfect control after SCRs are turned ON/OFF based on the applied gate signals. In general, these are preferable over their uncontrolled equivalents. A thyristor is another name for a silicon-controlled rectifier (SCR). It is a three-terminal diode with Anode, Cathode, and gate terminals.
Similar to a normal diode, this will perform in forwarding bias whereas, in reverse bias, it blocks current however it starts only in forward conduction once there is a signal at the input of the gate terminal. This plays an important role in output voltage control.
Types of Filters used in Rectifiers
Rectifier circuits produce a DC-like output, however, when we use a bridge rectifier, the output contains some AC components as well as DC components. To reduce the AC component, various types of filters are utilised at the rectifier's output face. Capacitors and inductors are the most common filters used in rectifiers.
A capacitor can be connected in parallel in a filter circuit since it allows AC and inhibits DC. At the output, any alternating current component will pass through the capacitor in the direction of the ground, resulting in a low quantity of alternating current in the output.
In a filter circuit, an inductor can be connected in series because it has inductive reactance. This reactance is an opposition to any changes, and it gives high impedance to AC and low impedance to DC because DC is a stable signal whereas AC fluctuates over time.
An L-section filter can be used based on the configuration of a capacitor and inductor. This type of filter consists of a series-connected inductor and a parallel-connected capacitor. The Pi section filter consists mostly of two capacitors connected in parallel via an inductor connected in series.
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:
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.
In diodes, the current-carrying capacity is low, while the position in rectifiers is high.
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.
Rectifiers are used in a computer system, while diodes are used in switches and clippers.
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 the 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.
Diodes and rectifiers are important topics to learn in physics. These two topics are quite important in the chapter on electricity that students need to focus on. Understanding these two topics will enhance your conceptual foundation in this chapter and will help you score well in the exams.
FAQs on Difference Between Diode and Rectifier for JEE Main 2024
1. What are Special - Purpose Diodes and Their Applications?
There are some particular purpose diodes that serve a few specific functions. There are many such particular purpose diodes like 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?
Diodes are present in basically every home appliance such as phones, LEDs, laptops, TVs, 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 that is grey. The other is a black coloured n-type semiconductor. Diodes are mostly electronic devices that protect the home appliances such as lights and remote controls in televisions and radio players. While connecting the diode make sure not to mix up the connections. Current will not flow if the connections are not proper.
3. Why are diodes important?
Diodes’ main purpose is regularisation of current flow in a circuit. A diode is one of the simplest semiconductor components in a circuit. Diodes perform a wide range of very useful functions. Even though the core reason for a diode is to manage the flow of electrical currents direction. Diodes ensure that the electrical current flows only in one direction through them and does not allow the current to pass back to its source. Hence, diodes are very important in a circuit. Visit Vedantu to understand the importance of diodes and rectifiers at a glance.
4. Do Diodes have polarity?
Yes, Diodes are polarised components, which means they must be linked in a specific orientation in order to function properly in a circuit. A physical diode has two terminals that protrude from a tin can form in the middle. The positive terminal, known as the anode, is on one side. The negative end, known as the cathode, is the other terminal. Returning to our electrical flow, current in a diode can only go from the anode to the cathode, never the other way around.
5. Is a Diode a Rectifier?
In simple terms, a diode allows the current to flow in only one way. This unique attribute of the diode enables it to function as a rectifier by converting an alternating current source to a direct current source.
A rectifier is a diode that transforms alternating current (AC) to direct current (DC) (DC). This is an important process because alternating current can reverse direction on a regular basis, whereas direct current flows in a single direction and is thus easier to govern.