Ohmic Conductor And Non Ohmic Conductor

Ohmic vs. Non-Ohmic Conductors: Understanding the Difference

Understanding the behavior of materials when electricity passes through them is fundamental to electronics and electrical engineering. This article explores the crucial distinction between ohmic and non-ohmic conductors, explaining their characteristics, examples, and applications. We'll delve into Ohm's Law and how it applies (or doesn't apply) to each type, providing a comprehensive guide for both beginners and those seeking a refresher.

What is an Ohmic Conductor?

An ohmic conductor is a material that obeys Ohm's Law. Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across it, provided the temperature and other physical conditions remain constant. Mathematically, this is represented as:

V = IR

Where:

• V is the voltage (in volts)
• I is the current (in amperes)
• R is the resistance (in ohms)

This means that the resistance (R) of an ohmic conductor remains constant regardless of the applied voltage or current. The current-voltage (I-V) graph of an ohmic conductor is a straight line passing through the origin.

Examples of Ohmic Conductors:

• Most metals: Copper, silver, gold, aluminum, and others are excellent examples. Their resistance changes slightly with temperature, but within a reasonable range, they behave ohmically.
• Resistors (within their operating range): These components are specifically designed to exhibit a consistent resistance value.

Characteristics of Ohmic Conductors:

• Linear I-V characteristic: The current is directly proportional to the voltage.
• Constant resistance: Resistance remains constant over a wide range of voltages.
• Temperature dependence: Resistance changes with temperature, but the relationship is usually predictable.

What is a Non-Ohmic Conductor?

A non-ohmic conductor is a material that does not obey Ohm's Law. Its resistance changes depending on the applied voltage or current, or other factors like temperature and light intensity. The I-V graph of a non-ohmic conductor is not a straight line.

Examples of Non-Ohmic Conductors:

• Diodes: These semiconductor devices allow current to flow easily in one direction but offer high resistance in the opposite direction.
• Light-emitting diodes (LEDs): Similar to diodes, their resistance varies with the applied voltage and current.
• Transistors: These semiconductor devices are used for amplification and switching; their resistance varies significantly based on the applied voltage.
• Thermistors: These are temperature-sensitive resistors whose resistance changes dramatically with temperature.
• Varistors: These voltage-dependent resistors change their resistance based on the applied voltage.
• Electrolytic capacitors: These capacitors exhibit non-linear behavior at high frequencies or voltages.

Characteristics of Non-Ohmic Conductors:

• Non-linear I-V characteristic: The relationship between current and voltage is not linear.
• Variable resistance: Resistance depends on factors like voltage, current, temperature, or light intensity.
• Complex behavior: Their electrical behavior is often more complex and depends on multiple factors.

Applications:

The difference between ohmic and non-ohmic conductors leads to their use in various applications. Ohmic conductors are fundamental in electrical wiring and circuits, while non-ohmic conductors are essential in various electronic devices and applications which require controlling or modulating the flow of current. For example, diodes are used for rectification, LEDs for lighting, and transistors are the building blocks of modern electronics.

Conclusion:

Understanding the distinction between ohmic and non-ohmic conductors is crucial for anyone working with electricity and electronics. While ohmic conductors provide a simple and predictable response, non-ohmic conductors enable the sophisticated control and manipulation of electrical signals essential for modern technology. This article provides a solid foundation for further exploration into the fascinating world of electrical materials and their behavior.