Negative temperature coefficient

Definition

A negative temperature coefficient refers to a property of certain materials where their electrical resistance decreases as the temperature increases. This behavior is typical in semiconductors and some metallic materials, allowing them to conduct electricity more efficiently at higher temperatures. Understanding this concept is crucial for applications in electronics and temperature sensors.

5 Must Know Facts For Your Next Test

1. Negative temperature coefficients are commonly found in semiconductors, like silicon and germanium, which are widely used in electronic devices.
2. As the temperature of a material with a negative temperature coefficient rises, more charge carriers become available, reducing resistance.
3. These materials can be used in thermistors, which are temperature-sensitive resistors that can be employed in various electronic circuits.
4. A negative temperature coefficient allows for better thermal stability in electronic components by reducing power loss at higher temperatures.
5. The behavior of materials with negative temperature coefficients is critical in designing circuits that rely on precise temperature measurements or control.

Review Questions

• How does the behavior of materials with a negative temperature coefficient impact their use in electronic devices?
  • Materials with a negative temperature coefficient are beneficial in electronic devices because they allow for increased conductivity as temperatures rise. This property enhances the efficiency of semiconductors used in transistors and diodes, as more charge carriers become available to facilitate current flow. As a result, devices can operate more effectively under varying thermal conditions, making them essential for modern electronics.
• Discuss the differences between materials with negative and positive temperature coefficients in terms of their applications.
  • Materials with negative temperature coefficients are primarily used in applications where increased conductivity with rising temperatures is desired, such as thermistors and semiconductor devices. In contrast, materials with positive temperature coefficients are often used in safety applications, like fuses, where increased resistance at higher temperatures helps prevent overheating. Understanding these differences helps engineers select appropriate materials for specific electronic applications based on thermal behavior.
• Evaluate the significance of understanding negative temperature coefficients when designing circuits that require precise thermal management.
  • Understanding negative temperature coefficients is crucial for circuit design that demands precise thermal management since these properties influence how components behave under varying temperatures. Designers must consider how changes in resistance affect current flow to ensure reliability and performance. For instance, incorporating thermistors into feedback loops can help regulate temperatures, preventing overheating or underperformance in sensitive electronic systems. Thus, grasping the concept of negative temperature coefficients aids engineers in creating efficient and stable circuit designs.

Related terms

Positive Temperature Coefficient:

A characteristic of materials where their electrical resistance increases with an increase in temperature, common in many metals.

Semiconductors: Materials whose electrical conductivity falls between that of conductors and insulators, often exhibiting a negative temperature coefficient.

Resistivity:

A measure of how strongly a material opposes the flow of electric current, which can change with temperature in materials exhibiting temperature coefficients.