Increased Resistance

Definition

Increased resistance refers to a rise in the opposition to the flow of electric current through a conductor, often influenced by various external factors. One of the primary factors affecting resistance is temperature; as temperature rises, the atoms in a conductor vibrate more, leading to more collisions between electrons and atoms, which increases resistance. This phenomenon is crucial in understanding how electrical devices operate under different thermal conditions.

5 Must Know Facts For Your Next Test

1. In most conductors, resistance increases with temperature due to increased atomic vibrations that obstruct electron flow.
2. For materials like semiconductors, resistance can decrease with rising temperature, showcasing contrasting behavior compared to metals.
3. The formula for calculating resistance changes with temperature can be expressed as $$R_T = R_0(1 + eta(T - T_0))$$ where $$R_T$$ is the resistance at temperature $$T$$, $$R_0$$ is the original resistance at a reference temperature $$T_0$$, and $$eta$$ is the temperature coefficient of resistance.
4. Increased resistance leads to higher power losses in electrical systems, often manifesting as heat in devices, which can impact their efficiency.
5. Understanding how increased resistance impacts current flow is vital for designing circuits and choosing appropriate materials for specific applications.

Review Questions

• How does an increase in temperature affect the resistance of typical conductors and why is this important for circuit design?
  • An increase in temperature generally causes the resistance of typical conductors to rise due to increased atomic vibrations leading to more frequent collisions with electrons. This understanding is crucial for circuit design because higher resistance can result in lower current flow and increased power loss as heat. Engineers must account for these temperature effects to ensure circuits function reliably under varying thermal conditions.
• Compare and contrast how temperature affects the resistance of metals versus semiconductors and discuss implications for their use in electronics.
  • For metals, an increase in temperature results in higher resistance due to greater atomic vibration. Conversely, semiconductors often exhibit decreased resistance with increasing temperature as more charge carriers become available. This distinct behavior means that metals are typically used for wiring where stability under thermal changes is essential, while semiconductors are utilized in applications such as sensors and transistors where variable conductivity is beneficial.
• Evaluate the practical implications of increased resistance due to temperature changes in electrical devices and how it impacts energy efficiency.
  • Increased resistance due to rising temperatures in electrical devices leads to higher power losses primarily manifested as heat. This not only reduces the energy efficiency of the device but can also lead to overheating, potential failure, or reduced lifespan of components. Designers must consider these thermal effects when creating systems, implementing cooling solutions or selecting materials that can operate efficiently across expected temperature ranges.

Related terms

Conductivity: A measure of a material's ability to conduct electric current, inversely related to resistance.

Ohm's Law: A fundamental principle that relates voltage, current, and resistance in an electrical circuit, stating that voltage equals current times resistance (V = I × R).

Resistivity: An intrinsic property of materials that quantifies how strongly a given material opposes the flow of electric current, affecting overall resistance.