Orthopedic implants are used to fixate the bone fragments of fractures. Novel smart implants are now being developed that can continuously monitor and actively promote bone healing—by, for example, micro-massaging the fracture ...
Mar 27, 2024
0
0
The Terasaki Institute for Biomedical Innovation (TIBI) has developed a novel organ-on-a-chip device for measuring electrical resistance across endothelial barriers. This chip had carbon-based, screen-printed electrodes incorporated ...
Oct 25, 2023
0
0
It can be challenging to create a treatment plan for depression. This is especially true for patients who aren't responding to conventional treatments and are undergoing experimental therapies such as deep brain stimulation. ...
Sep 21, 2023
0
4
The sequencing of the human genome promised a revolution in medicine, but scientists soon realized that a genetic blueprint alone does not show the body in action. That required understanding the proteome—all the proteins, ...
Sep 11, 2023
0
183
High levels of lean muscle might protect against Alzheimer's disease, suggests a large study published in the open access journal BMJ Medicine. However, further research is needed to tease out the underlying biological pathways, ...
Jun 29, 2023
0
111
Not only is depression a debilitating disease, but it is also widespread. Approximately 20 million adult Americans experience at least one episode of depression per year.
Nov 17, 2022
0
14
A group of researchers in the Madrid region have developed and patented a new smart mask with an innovative design that can monitor a wearer´s vital signs from up to 20 km away.
Nov 14, 2022
0
17
Cycling is a great way to stay in shape. You get outdoors with plenty of fresh air, and it is an easy and gentle way to improve your fitness and circulation and strengthen your heart and muscles.
Oct 6, 2022
0
15
Deep brain stimulation (DBS) to the superolateral branch of the medial forebrain bundle (MFB), which is linked to reward and motivation, revealed metabolic brain changes over 12 months post-DBS implantation, making it a strong ...
Aug 19, 2022
0
181
Over the years, everyone loses a few brain cells. A study led by scientists from USC Stem Cell and the USC Neurorestoration Center presents evidence that adults can replenish at least some of what they've lost by generating ...
Apr 5, 2022
0
52
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
