Georg Simon Ohm was the German mathematician and physicist eternally recognized for having postulated the so-called Ohm's law. The unit of electrical resistance is the ohm, symbolized by the Greek letter omega.
Ohm's Law is the name that identifies a key postulate for understanding the fundamentals of an electrical circuit . Included in this name is the surname of Georg Simon Ohm , the mathematician and physicist of German origin whose identity has also been exalted by choosing how to name the ohm (unit of resistance) .
As has been established, since Ohm 's original statement came out, various generalizations have been made. This principle indicates that the potential difference (or voltage ) applied at each end of an electrical conductor is directly proportional to the intensity of current flowing through the aforementioned conductor. This content was deepened when Ohm added the idea of electrical resistance , as understood as the proportionality factor that arises from the link between the aforementioned potential difference and the electric current . The Prussian physicist Gustav Robert Kirchhoff complemented this law in 1845 with his own contributions that are essential for analyzing circuits in the fields of electronics and electricity .
It should be noted that Kirchhoff's laws are two. One points out that the sum of intensities oriented in the direction of a node (that is, to a point where at least three conductors converge) is equal to the sum of the currents leaving that node. The remainder accounts for the null result arising from adding the voltage drops or potential differences in a closed circuit .
Features of Ohm's Law
Ohm's law was born and enriched thanks to studies and use of modified resources carried out by Georg S. Ohm . He learned about previous work by his colleagues on electric current and voltage . He also developed and transformed devices to carry out experiments. This happened, for example, with the Coulomb torsion balance , to which a magnetic bar, a voltaic cell, multiple cables and mercury receptacles were added with the aim of designing a circuit . The intention, at that time, was to use this structure to mathematically link the drop in the electromagnetic force formed by a current flowing along the length of a certain cable.
The electrical resistance , the current intensity – measured in Ampere (current unit) – and the electric potential difference – expressed in Volt (voltage unit) – are combined in this statement that can be approached from the notion of impedance and give impulse to the so-called Ohm's law directed to circuits that are crossed by an alternating current (AC) . There is, on the other hand, the macroscopic or classical Ohm's law . This indicates that in certain materials (frequently metallic conductors), the electric field and current density are related through conductivity , a constant specific to each particular substance. It is interesting to note that, especially in semiconductor elements (categorized as non-ohmic or non-linear), the resistance is not constant as it is in metals and other conductors classified as ohmic or linear, regardless of the amount or level of current that is applied.
Ohm's law is useful in establishing the link between resistance, current and voltage within an electrical circuit.
Practical applications
Ohm's law has a wide variety of practical applications . It is important since, for example, it allows minimizing or preventing the chances of an electric shock or a voltage drop occurring through a calculation of voltages and currents prior to the step of connecting the circuit . Within this framework, the consumption of electrical energy can be determined in a simple way and alternatives can be discovered to make an electrical installation more efficient.
Nor should it be overlooked that both Ohm's law and Joule's law are related to the operation and type of use of many household appliances.
The intensity of the electric current is measured with an ammeter, while the potential differences are determined with the voltmeter.
Examples of Ohm's Law
Taking into consideration Ohm's law in order to carry out the corresponding mathematical calculations, electrical installations can generally be carried out in everyday life. This postulate is also used to analyze the failure that is identified with the name short circuit . It is possible to practice these equations by solving exercises in which resistance is put into play and one must find out what current flows through it or what power an incandescent lamp dissipates, to propose some alternatives.
To ensure that a certain current can circulate through a closed circuit , it is also essential that energy is provided (called electromotive force) capable of generating a potential difference and establishing the electric field capable of accelerating the charges.
On the other hand, you can work with Ohm's law in a series circuit (applying it to each of the individual resistors) or take advantage of it in a parallel circuit (in this case, as there is an identical voltage in each of the resistances). branches and the total current arises from adding the currents of each branch, the postulate is applied to each of the branches).