Unit Information
Microohm
A metric subunit of electrical resistance equal to one millionth of an ohm (10⁻⁶ Ω). Used for ultra-low resistance measurements in high-conductivity materials, superconductors, and precision electrical systems. Essential for characterizing bulk material conductivity, contact resistance in high-current applications, and resistance of large conductors. Critical in power distribution systems, electrical busbar design, and materials science research where minute resistance variations significantly impact performance and energy efficiency.
Milliohm
A metric subunit of electrical resistance equal to one thousandth of an ohm (10⁻³ Ω). Commonly used for measuring low resistance values in conductors, connectors, and electrical components. Essential for characterizing contact resistance, wire resistance, and shunt resistor measurements. Widely employed in power electronics, battery testing, and precision electrical measurements where small resistance values significantly impact system performance and efficiency calculations.
Conversion Tips
- Remember to check your decimal places for accuracy.
- This conversion is commonly used in international applications.
- Consider the context when choosing precision levels.
- Double-check calculations for critical applications.
Learn More About Electric_resistance
Scientific Overview
Electric resistance is the opposition to the flow of electric current through a material. It converts electrical energy into heat and is measured in ohms (Ω). Resistance depends on material properties, dimensions, and temperature.
Historical Background
Georg Simon Ohm formulated Ohm's Law in 1827, establishing the fundamental relationship between voltage, current, and resistance. The unit ohm is named after him.
Real-World Applications
Electronics
Resistors control current flow and divide voltages in circuits.
Electrical Engineering
Resistance calculations determine power losses in transmission lines.
Materials Science
Resistivity measurements identify materials and detect defects.
Temperature Sensing
Thermistors use resistance changes to measure temperature.
Interesting Facts
- Copper wire has very low resistance, making it ideal for electrical wiring.
- The human body has a resistance of about 100,000 ohms when dry.
- Superconductors have exactly zero electrical resistance below critical temperature.
- Carbon resistors can withstand high temperatures and are very stable.
Key Formulas
Resistance Definition
R = V/IResistivity
R = ρ·L/APower Dissipation
P = I²R = V²/RTemperature Dependence
R = R₀[1 + α(T - T₀)]