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Difference Between Ohmic and Non Ohmic Conductors for JEE Main 2024

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What is Ohmic and Non Ohmic Conductors: Introduction

To differentiate between ohmic and non ohmic conductors: Ohmic and non ohmic conductors are two categories of materials that exhibit different behaviors when an electric current passes through them. Ohmic conductors, also known as ohmic resistors or linear resistors, follow Ohm's Law, which states that the current flowing through a conductor is directly proportional to the voltage applied across it. On the other hand, non ohmic conductors, also called non-linear resistors, do not obey Ohm's Law. The resistance of non ohmic conductors varies with the applied voltage or current, often exhibiting nonlinear behavior such as increasing or decreasing resistance as the voltage changes. This distinction between ohmic and non ohmic conductors is essential in understanding and analyzing electrical circuits and the behavior of different materials in response to electric currents. Read further for detail more about them. 


Category:

JEE Main Difference Between

Content-Type:

Text, Images, Videos and PDF

Exam:

JEE Main

Topic Name:

Difference Between Ohmic and Non Ohmic Conductors

Academic Session:

2024

Medium:

English Medium

Subject:

Physics

Available Material:

Chapter-wise Difference Between Topics


Defining Ohmic Conductors 

Ohmic conductors, also known as ohmic resistors or linear resistors, are materials that exhibit a consistent and linear relationship between the current passing through them and the voltage applied across them. In other words, ohmic conductors obey Ohm's Law, which states that the current flowing through a conductor is directly proportional to the voltage applied. The resistance of an ohmic conductor remains constant regardless of the magnitude of the applied voltage. This predictable behavior allows for easy calculation and analysis of electrical circuits containing ohmic conductors. Examples of ohmic conductors include most metals, such as copper and aluminum, which have a relatively constant resistance over a wide range of voltages and currents. The characteristics of ohmic conductors are: 


  • Linear Relationship: Ohmic conductors exhibit a linear relationship between the current flowing through them and the voltage applied across them, adhering to Ohm's Law.

  • Constant Resistance: The resistance of an ohmic conductor remains constant over a wide range of applied voltages and currents. This allows for straightforward calculations and predictions in electrical circuits.

  • Predictable Behavior: Ohmic conductors follow predictable patterns and can be easily modeled and analyzed using mathematical equations.

  • Stable Electrical Properties: Ohmic conductors maintain their resistance characteristics over time, exhibiting consistent behavior under different operating conditions.

  • Low Temperature Dependency: Ohmic conductors typically have a relatively low temperature dependency, meaning their resistance doesn't vary significantly with changes in temperature.

  • Wide Application Range: Ohmic conductors, such as most metals, are widely used in electrical and electronic devices due to their stable and predictable behavior.


Defining Non Ohmic Conductors 

Non ohmic conductors, also known as non-linear resistors, are materials that do not follow Ohm's Law. Unlike ohmic conductors, the current-voltage relationship in non ohmic conductors is not linear. Instead, their resistance changes as the applied voltage or current varies. This non-linearity often results in a non-linear IV curve, where the resistance may increase or decrease with changing voltage or current. Non ohmic conductors can exhibit various behaviors such as negative temperature coefficient (NTC), positive temperature coefficient (PTC), or even voltage-dependent resistance. Examples of non ohmic conductors include semiconductor materials, thermistors, and certain electrolytes. Understanding the behavior of non ohmic conductors is important for designing circuits that involve these materials and for analyzing their responses to varying electrical conditions. The characteristics of non ohmic conductors are: 


  • Non-Linear Relationship: Non ohmic conductors do not follow a linear relationship between the current and voltage. Their resistance varies with changes in applied voltage or current.

  • Variable Resistance: The resistance of non ohmic conductors changes as the voltage or current changes. It can increase, decrease, or exhibit complex non-linear patterns.

  • Temperature Dependency: Non ohmic conductors often show a significant temperature dependency, meaning their resistance can change with variations in temperature.

  • Non-Ohmic Behavior: Non ohmic conductors can exhibit behaviors like negative temperature coefficient (NTC), where resistance decreases with increasing temperature, or positive temperature coefficient (PTC), where resistance increases with increasing temperature.

  • Application-Specific: Non ohmic conductors are utilized in various applications, such as thermistors for temperature sensing, varistors for surge protection, and semiconductor devices for electronic circuits.

  • Non-Linear IV Curve: Non ohmic conductors have non-linear current-voltage (IV) curves, reflecting their non-linear behavior and resistance variations.


Differentiate Between Ohmic and Non Ohmic Conductors

S.No

Category 

Ohmic Conductors 

Non Ohmic Conductors 

1

Current-Voltage Relationship

Follow Ohm's Law: Linear relationship between current and voltage

Do not follow Ohm's Law: Non-linear relationship between current and voltage

2

Resistance Behavior

Resistance remains constant regardless of voltage or current

Resistance changes with variations in voltage or current

3

IV Curve

Linear IV curve

Non-linear IV curve

4

Temperature Dependency

Typically have low temperature dependency

Often exhibit significant temperature dependency

5

Examples

Most metals such as copper, aluminum, etc.

Semiconductor materials, thermistors, certain electrolytes, etc.

6

Application

Used in everyday electrical circuits, power transmission, etc.

Used in specialized applications, sensors, surge protectors, etc.


This table provides a concise overview of the main difference between ohmic and non ohmic conductors, including aspects such as the current-voltage relationship, resistance behavior, IV curve, temperature dependency, examples of materials, and typical applications for each type of conductor.


Summary

Ohmic and non ohmic conductors are two types of materials that exhibit different behaviors when an electric current passes through them. Ohmic conductors, also known as linear conductors, obey Ohm's Law, which states that the current passing through the conductor is directly proportional to the applied voltage. Whereas, non ohmic conductors, also known as non-linear conductors, do not obey Ohm's Law. The resistance of ohmic conductors remains constant regardless of the applied voltage or current, while the resistance of non ohmic conductors is not constant and can vary with changes in voltage or current.

FAQs on Difference Between Ohmic and Non Ohmic Conductors for JEE Main 2024

1. Do ohmic conductors follow Ohm's Law?

Yes, Ohmic conductors do follow Ohm's Law. Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage applied across it, given that the temperature and other physical conditions remain constant. In ohmic conductors, such as most metals, the resistance remains constant over a wide range of applied voltages and currents. This means that as the voltage across an ohmic conductor increases, the current through it also increases proportionally. Similarly, if the voltage decreases, the current decreases accordingly. 

2. What are the applications of non ohmic conductors? 

Non ohmic conductors find various applications in electrical and electronic devices. One significant application is in semiconductor devices such as diodes and transistors. Diodes allow the flow of current in one direction and are used in rectifiers, voltage regulators, and signal processing circuits. Transistors, which are key components in amplifiers, switches, and logic circuits, control the flow of current based on input signals. Gas discharge tubes, another example of non ohmic conductors, are used for voltage regulation, surge protection, and in lighting applications like neon signs. 

3. How does the resistance of a non ohmic conductor behave with changes in voltage or current?

The resistance of a non ohmic conductor does not remain constant with changes in voltage or current. Unlike ohmic conductors, where resistance is constant, non ohmic conductors exhibit varying resistance. The resistance can increase or decrease with changes in voltage or current. This behavior is often attributed to factors such as temperature, material properties, or the presence of functional groups in the conductor. In some cases, the resistance may increase as the voltage or current increases (positive temperature coefficient), while in other cases, it may decrease (negative temperature coefficient). 

4. Can ohmic conductors exhibit non-linear behavior?

No, Ohmic conductors do not exhibit non-linear behavior. Ohmic conductors follow Ohm's Law, which states that the current flowing through a conductor is directly proportional to the voltage applied across it. This linear relationship between current and voltage implies that the resistance of ohmic conductors remains constant over a wide range of voltages and currents. Ohmic conductors, such as most metals, exhibit a linear response and maintain a constant resistance under normal operating conditions.

5. Give an example of a non ohmic conductor.

An example of a non ohmic conductor is a semiconductor material. Semiconductors, such as silicon or germanium, do not follow Ohm's Law and exhibit non-linear behavior. The resistance of semiconductors can be influenced by factors like temperature, doping levels, and applied electric fields, making them non ohmic conductors in contrast to the linear behavior of ohmic conductors like metals.