Electromotive force (EMF) is the voltage difference in electrical devices, generated by charge differences. It can be induced by chemical reactions, magnetic fields, and temperature differences. EMF is used in power generation and can be affected by mechanical and gravitational influences. It is named after Alessandro Volta and can be measured externally. New technology, such as nanomagnets, is being combined with EMF for magnetic sensors and quantum batteries.
Electromotive force (EMF) is the voltage difference between the terminals of a battery, generator, thermocouple, or other electrical device. It is typically defined as electric potential energy, which allows current to flow from one end of a circuit to the other. Charge differences are usually created when particles called electrons gather at one end and there are fewer at the other end. Amperes, voltage and internal resistance are calculated mathematically to determine the electromotive force, which is usually less than the total system voltage.
Voltaic cells often have distinct electromotive forces. These are usually triggered by chemical reactions where the surface of an electrode and an electrolyte substance meet. Induced electromotive force is commonly used in power generation plants and is often achieved using a coil or conductor. Magnetic fields and the shape of the electric circuit also affect induction, which can be static if the magnetic field does not change, or dynamic if the field around a conductor changes.
Nickel-cadmium, nickel-metal hydride, lead-acid and lithium-ion electric cells can produce an electromotive force. The concept was named after Alessandro Volta, the inventor of the battery. While it first referred to the force required to separate different charges, electromotive force was revised to characterize the strength of an electric field in the 1860s. It is typically generated by batteries, based on the placement of oppositely charged metal parts inside the devices.
A thermocouple generally has V-shaped metal components that produce an electromagnetic field when heated. Water heaters and fireplaces often work this way, while generators make use of it by wrapping a wire around a magnet. Chemical and magnetic forces can have an effect, as can mechanical and gravitational influences. Induction via rotors in a power building affects the electromotive force, while the heating and cooling elements of a thermoelectric device create a temperature difference that also affects electromagnetic fields.
The electromotive force of a power source is often determined by the strength of external measurements, based on their unit of charge. Ultimately it can be defined by how this gets an electric charge around the complete circuit, based on the use of a source. In the 21st century, technology such as nanomagnets is being combined with electromotive force in research. This could lead to highly sensitive magnetic sensors, as well as new battery varieties based on magnetic and quantum technology.
Protect your devices with Threat Protection by NordVPN
