Unveiling the Difference between Diode and Resistor

What is a diode?

  A diode is an electronic component that only allows current to flow in one direction. Additionally, it prevents the flow of electricity in the opposing direction. It is the most straightforward two-terminal unilateral semiconductor device, to put it another way. Anode and cathode refer to the diodes' two terminals. It is made up of a P-type and an N-type semiconductor that has been combined. Anode is the N-Type side, whereas Cathode is the P-Type side. Diverse uses for diodes exist, such as rectification, switching, and signal processing.    

Types of Diodes

PN Junction Diode:

  The most fundamental kind of diode is the PN junction type. It consists of two pieces of semiconductor material, one doped with p-type impurities and the other with n-type impurities. The p-type material has an excess of holes, whereas the n-type material has an excess of electrons. A depletion region arises at the junction where the two pieces of material are linked. The depletion zone acts as a restriction to the current flow. The depletion region contracts and current can flow through the PN junction diode when it is forward-biased (positive voltage supplied to the p-terminal and negative voltage applied to the n-terminal). The depletion region widens and current cannot pass through the PN junction diode when it is reverse biased (negative voltage applied to the p-terminal and positive voltage applied to the n-terminal). Power conversion, rectifying, and signal processing are just a few of the many uses for PN junction diodes.   Zener Diode:

  A Zener diode is a PN junction diode with reverse bias functionality. When a reverse-biased Zener diode achieves a specific threshold value, referred to as the Zener voltage, current can flow through the diode. The doping of the semiconductor material affects the Zener voltage. Applications for zener diodes include voltage regulation, voltage reference, and circuit protection.   Schottky Diode:

  A Schottky diode is a form of diode that lacks a p-n junction in favor of a metal-semiconductor junction. This results in quicker switching rates and a lower forward voltage drop for Schottky diodes compared to PN junction diodes. Logic circuits, high-frequency signal processing, and power conversion are just a few of the uses for Schottky diodes.   Light Emitting Diode (LED):

  An LED is a type of diode that produces light when electricity passes through it. The band gap of the semiconductor material affects the color of the light an LED emits. Lighting, displays, and optical communications are just a few of the many uses for LEDs.   Photodiode:

  A photodiode is a particular kind of diode that conducts current when exposed to light. The light's intensity determines how much current passes through the photodiode. Light sensing, optical communications, and solar cells are just a few of the uses for photodiodes.  

What is a resistor?

A resistor is a passive electrical component that prevents current from flowing. It is an electronic component that is used to build a specific amount of resistance into a circuit. Therefore, a resistor can also be referred to as a two-terminal passive device. Carbon or metal wire is typically used in their construction. These parts were designed to have a consistent resistance value. They come in a range of sizes and forms. They also have a wide range of uses, such as load matching, voltage division, and current limiting.

 

Types of Resistors

Carbon Composition Resistors: One of the earliest and most basic forms of resistors is the carbon composition resistor. They are created by combining a resin binder and carbon powder and then shaping the mixture into a cylindrical shape. Resistors with a carbon composition have a wide resistance range and are reasonably affordable, but they are also less precise and have a shorter lifespan than other types of resistors.

  Metal Film Resistors:

  By depositing a thin layer of metal onto a ceramic substrate, metal film resistors are created. While more expensive than carbon composition resistors, metal film resistors are more precise and last longer.   Wirewound Resistors: A length of resistance wire is twisted around a ceramic core to create wire-wound resistors. Although wire-wound resistors are the largest and most expensive resistors, they are also exact and have a high power rating.

  Thick Film Resistors:

  A thick metal film is deposited onto a substrate material to create thick film resistors. Although thick film resistors have a larger power rating and are less expensive, they are less precise than thin film resistors.   Surface Mount Resistors (SMDs): Small resistors called surface mount devices (SMDs) are made to adhere directly to the surface of a printed circuit board (PCB). SMDs are used in a wide range of electronic devices and come in a variety of different sizes and packaging.

 

Video related to Diode vs. Resistor

 

How does a diode work?

A diode's depletion region contracts and current can flow through it when it is forward-biased (positive voltage supplied to the p-terminal and negative voltage applied to the n-terminal). The depletion region widens and current cannot flow through a diode when it is reverse biased (negative voltage supplied to the p-terminal and positive voltage applied to the n-terminal). The following diagram shows the structure of a PN junction diode and how it works under forward and reverse bias conditions:

  Under forward bias, the negative voltage at the n-terminal repels holes from the p-terminal while the positive voltage at the p-terminal draws electrons from the n-terminal. As a result, the depletion region contracts and the diode may conduct current. With reverse bias, the p-terminal's positive voltage repels electrons from the n-terminal while the n-terminal's negative voltage draws holes from the p-terminal. Due to the widening of the depletion region as a result, the diode is unable to conduct current.  

How to Test a Diode?

There are two main ways to test a diode: using a multimeter or using a diode tester. Set the multimeter to the diode mode before testing a diode. Next, attach the multimeter's positive lead to the diode's anode and its negative lead to the diode's cathode. The multimeter will show a forward voltage drop of roughly 0.7 volts if the diode is in excellent operating order. A voltage drop of zero volts or a voltage drop that is much higher than 0.7 volts will be shown on the multimeter if the diode is not functioning properly. Simply attach the diode to the tester to conduct a diode test. The tester for the diode will light up if it is in good operating condition. The tester for the diode won't light up if the diode isn't functioning correctly.  

How does a resistor work?

By converting electrical energy into thermal energy, resistors function. Current encounters resistance as it passes through a resistor. The resistor heats as a result of this resistance. The square of the current passing through the resistor determines how much heat is produced.  

Differences between diodes and resistors

The following table summarizes the key differences between diodes and resistors:

Characteristic	Diode	Resistor
Function	Allows current to flow in one direction only	Resists the flow of current
Symbol	D	R
Current-voltage relationship	Non-linear	Linear
Applications	Rectification, switching, signal processing	Voltage division, current limiting, load matching

 

Applications of Diodes

• Rectification: To transform AC electricity into DC voltage, diodes are needed. Restitution is the term for this. Power supply and other electronic devices employ rectifiers.
• Switching: Diodes can be used to turn on and off electrical circuits. Applications like lighting control and motor control can benefit from this.
• Voltage regulation: Zener diodes are devices that can be used to control voltage. Applications like power supply and battery-operated gadgets can benefit from this.
• Light emission: LEDs are utilized to produce light, which is emitted. They are frequently employed in lighting and display applications.
• Laser emission: Coherent light beams are created using laser diodes. They are utilized in optical devices such as lasers.

 

Applications of Resistors

• Current limiting: Resistors can be used for current limiting to control how much current is allowed to pass through a circuit. For the sake of preventing harm to delicate components, this is crucial. For instance, a resistor is connected in series with an LED to control the current and guard against LED burnout.
• Voltage division: Resistors can be used to divide a voltage into two smaller voltages for voltage division. This helps use a single voltage source to power many circuits. A voltage divider, for instance, is frequently employed in digital circuits to generate a reference voltage.
• Feedback: Resistors can be used to give amplifiers and other circuits feedback. The circuit may be made more stable and perform better by using this feedback. For instance, an operational amplifier's feedback loop uses a resistor to set the gain and stabilize the amplifier.
• Filtering: Unwanted signals in a circuit can be removed using resistors. A resistor-capacitor (RC) filter, for instance, is utilized to remove high-frequency noise from a power source.
• Timing: Timing circuits can be built using resistors. For instance, a delay circuit can be built using an RC circuit.

 

Conclusion

In conclusion, diodes and resistors are essential parts of electronics. They serve several purposes and are included in numerous circuit types. Diodes allow current to flow solely in one direction, whereas resistors block the flow of current. Electronics amateurs and professionals may build circuits and debug electronic systems more effectively by learning the distinctions, types, functions, and applications of various electronic components. The diversity and usefulness of diodes in contemporary technology cannot be stressed, whether it is the use of diode lasers in numerous industries or the significance of data diodes in secure data transport. We open up a world of opportunities for innovation and development in the field of electronics by digging into the world of diodes.