New power cables in Europe to make energy cheaper and more sustainable
EU researchers are looking to improve the electric grid to reduce energy waste, cut costs and curb emissions.
May 30, 2024
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30
Engineering
EU researchers are looking to improve the electric grid to reduce energy waste, cut costs and curb emissions.
May 30, 2024
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30
Electronics & Semiconductors
Artificial neural networks may soon be able to process time-dependent information, such as audio and video data, more efficiently. The first memristor with a "relaxation time" that can be tuned is reported today in Nature ...
May 20, 2024
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64
Engineering
Controlling heat flow is key to enhancing performance in a wide variety of systems. In electronic devices, such as mobile phones or any type of processor, overheating decreases their performance and reduces their lifetime. ...
Apr 11, 2024
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54
Electronics & Semiconductors
Scientists have achieved a breakthrough in the development of non-volatile phase change memory—a type of electronic memory that can store data even when the power is turned off—in a material that has never displayed the ...
Sep 6, 2023
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74
Energy & Green Tech
Most electric vehicles are equipped with an electronic brain that manages day-to-day battery performance and safety. This battery management system, or BMS, includes software that uses algorithms to monitor the overall health ...
Aug 21, 2023
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17
Hardware
Researchers have developed a new design for computer memory that could both greatly improve performance and reduce the energy demands of internet and communications technologies, which are predicted to consume nearly a third ...
Jun 23, 2023
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80
Engineering
The basic principle of the atomic force microscope is very simple: an extremely thin, movable tip on a cantilever is moved over a surface that is being examined. Tiny forces on an atomic scale act between the tip and the ...
May 17, 2023
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11
Robotics
Artificial muscles and nerves made from the shape memory alloy nickel-titanium are making robot arms as supple and agile as their animal counterparts. But these artificial limbs also weigh less, will work tirelessly and can ...
Apr 4, 2023
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8
Engineering
Superconductors make highly efficient electronics, but the ultralow temperatures and ultrahigh pressures required to make them work are costly and difficult to implement. Room-temperature superconductors promise to change ...
Mar 28, 2023
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6
Hardware
Developing energy efficient high performing computing devices (i.e., devices that not only consume little power, but also compute information rapidly) is a key goal of edge computing research. Combining the memory components ...
Jan 30, 2023
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4
The electrical resistance of an object is a measure of its opposition to the passage of a steady electric current. An object of uniform cross section will have a resistance proportional to its length and inversely proportional to its cross-sectional area, and proportional to the resistivity of the material.
Discovered by Georg Ohm in the late 1820s, electrical resistance shares some conceptual parallels with the mechanical notion of friction. The SI unit of electrical resistance is the ohm, symbol Ω. Resistance's reciprocal quantity is electrical conductance measured in siemens, symbol S.
The resistance of a resistive object determines the amount of current through the object for a given potential difference across the object, in accordance with Ohm's law:
where
For a wide variety of materials and conditions, the electrical resistance does not depend on the amount of current through or the amount of voltage across the object, meaning that the resistance R is constant for the given temperature. Therefore, the resistance of an object can be defined as the ratio of voltage to current:
In the case of nonlinear objects (not purely resistive, or not obeying Ohm's law), this ratio can change as current or voltage changes; the ratio taken at any particular point, the inverse slope of a chord to an I–V curve, is sometimes referred to as a "chordal resistance" or "static resistance".
This text uses material from Wikipedia, licensed under CC BY-SA