The formula for voltage in physics is the representation of electric potential energy per unit charge. If the current was placed in a certain place, the voltage indicates its potential energy at this point. In other words, it is a measurement of the force contained in an electric field or circuit at a given point. It is equal to the work that would have to be performed per unit of charge against the electric field in order to move it from one point to another.
Voltage is a scalar quantity, it has no direction. Ohm's law states that the intensity is equal to the current temporary resistance.
Units in the formula
In the formula for determining the voltage, the SI value is volt. Thus, 1B = 1 joule / pendant. Volt is named after the Italian physicist Alessandro Volta, who invented the chemical battery.
This means that in the physics formula, one coulomb of a charge will receive one joule of potential energy when it is moved between two points, where the electric potential difference is one volt. At a voltage of 12, one pendant of charge will receive 12 joules of potential energy.
A six-volt battery has the potential for one pendant of charge to receive six joules of potential energy between two locations. A nine-volt battery has the potential for one pendant of charge to receive nine joules of potential energy.
How the law works in real life
The stress formula in physics is sometimes very difficult to understand. A more concrete real-life example is a water tank with a hose going down below. A fluid is an accumulated charge. It takes work to fill the tank with water. This creates a supply of fluid. Like charge sharing in a battery. The more it is in the tank, the stronger the pressure - and water can escape through the hose with more energy. If there was less fluid in the aquarium, it would come out with a minimal amount of intensity.
Plain water example
This pressure potential is equivalent to voltage. The more water in the tank, the greater the impact. The more powerful the charge is stored in the battery, the higher the voltage.
When you open the hose, a stream of water flows. The pressure in the tank determines how quickly it flows. Electric current is measured in amperes. The higher the volt, the stronger the current. So, the stronger the water pressure, the faster it will flow out of the tank.
However, the current also depends on the resistance. In the case of a hose, this is its width. A wide pipe allows more water to pass through in less time, and a narrow pipe resists fluid flow. With electric current, there can also be resistance measured in Ohms.
What formula determines the voltage?
Ohm's law states that U is equal to the current temporary resistance.
V = I * R
If it is a 12-volt battery, then its value is two ohms, and the current will be six amperes. If the resistance was one ohm, the current would be 12 amperes.
The formula for voltage in physics says that intensity, the difference in electrical potential and pressure, is the difference between two points. The difference in this case between two objects (i.e., their voltage) in a static electric field is defined as the work required per unit charge to move the test reserve between points. In the International System of Units, the resulting block is called voltage.
Different quantities used
In SI, work is expressed in joules per pendant, where 1 volt = 1 joule per 1 pendant. The official definition of SI for a volt uses power and current, where 1 volt = 1 watt (power) per 1 ampere (current). This definition is equivalent to the more commonly used joule per pendant. Voltage or electric potential difference is denoted symbolically by DV, but more often simply as V, for example, in the context of Ohm or the Kirchhoff Rules.
Differences in the electric potential between points can be caused by a charge, a current through a magnetic field, or some combination of these three components.
A voltmeter can be used to measure voltage (or potential difference) between two points in the system; often, a common reference potential, such as system grounding, is used as a single object. Voltage can be either an energy source (electromotive force) or lost, used, or accumulated (potential drop) energy.
There are several useful ways to find out which voltage formula is needed in a particular case.
Roughly speaking, the force is determined so that negatively charged objects are attracted to higher voltages, and positively to lower ones. Therefore, the usual current in a wire or resistor always flows from smaller to larger.
Historically, the formula for the law of stress was mentioned using a term such as pressure. Even today, “tension” is still used in this context, for example, in the term “high voltage”, which is usually used in electronics based on thermionic valves (vacuum tubes).
How to find tension, formula. Electric field potential
An increase in voltage from some point x A at some point x B is given by someone.
In this formula for calculating the voltage, an increase from point A to B is equal to the work that would have to be performed per unit of charge, against the electric field, in order to move the particle from A to B without causing any acceleration. Mathematically, this is expressed as a curved integral of the electric field along this path. According to this definition, the voltage difference between two points is not formed unambiguously when there are time-varying magnetic fields, since the electric force is not conservative in such cases.
If this definition of voltage is used, any circuit in which time-varying magnetic fields exist, for example, rows containing inductors, will not have a clearly defined voltage between the nodes in the circuit. However, if magnetic fields are properly contained in each component, then the electric is conservative in the external region, and the components are well defined in it. In this case, the voltage at the inductor, when viewed from the side, is.
Despite the fact that the internal electric field in the coil is equal to zero (provided that it is an ideal conductor). There are several other ways to find out which voltage formula is needed in a particular case.
Determination through decomposition of an electric field
Using the above concept, the potential is not in one place when magnetic fields change with time. In physics, it is sometimes useful to generalize the electrical value, considering only the conservative part of the field. This is done using the following decomposition used in electrodynamics.
In the above formula, E - induced - rotational electric field due to time-varying magnetic backgrounds. In this case, the force between the points is always determined uniquely.
Another way
Let us examine the formula of mechanical stress in physics, the theory of chains.
In circuit analysis and electrical engineering, the force on the inductor is not considered zero or uncertain, as the standard definition suggests. This is because electrical engineers use a lumped element model to represent and analyze circuits.
It is assumed that there are no magnetic fields in the region of the surrounding series, and their influence is contained in “lumped elements”, which are idealized and autonomous components of the circuit used to model physical components. If the assumption of minor field leaks is too inaccurate, their effects can be modeled by spurious components.
However, in the case of a physical inductor, an ideal representation with lumped parameters is often accurate. This is due to the fact that the leakage fields in the inductance are usually insignificant, especially if the charge is a toroid. If the leaked fields are small, you can find that is path independent, and there is a clearly defined voltage at the inductor terminals. This is the reason that measurements with a voltmeter on the coil are often sufficiently independent of the location of the test leads.
Hydraulic analogy
A simple parallel for the electrical circuit in the voltage change formula is water flowing through a closed pipe, driven by a mechanical pump. This can be called a "water circuit." The potential difference between the two points corresponds to the difference in pressure between them. If the pump creates a pressure drop, then the water flowing from one flask to another can perform work, for example, set the turbine in motion. Similarly, work can be performed by electric current controlled by the potential difference provided by the battery. For example, a voltage that is sufficiently charged by a car battery can push a large current through the windings of the starter motor. If the pump does not work, it does not create a pressure difference, and the turbine does not rotate. Similarly, if the car’s battery is very weak or discharged, it will not rotate the starter.
Hydraulic analogy is a useful way to understand many electrical concepts. In such a system, the voltage is calculated by the pressure formula times the volume of the charge being transported. In an electric circuit, the work performed to move particles or other carriers is equal to the “electric pressure” multiplied by the number of electroparticles moved. The greater the differential pressure between two points in relation to the flow (potential difference or differential pressure of water), the greater the distance between them (electric current or water flow).
Measuring instruments
Instrumentation for determining the voltage includes a voltmeter, potentiometer and oscilloscope. The first works by measuring the current through a fixed resistor, which, according to Ohm's law, is proportional to the voltage. A potentiometer works by balancing an unknown voltage with a known voltage in a bridge circuit. The cathode-ray oscilloscope calculates by amplifying U and using it to deflect the electron beam from a direct path.
Typical voltages
The total flow for flashlight batteries is 1.5 V. And the joint voltage for car batteries is 12 volts.
The total power supplied by large energy companies to the consumer is from 110 to 120 volts and from 220 to 240 volts. The voltages in the energy transfer used to distribute all the current from power plants can be several hundred times greater than any consumer voltage, usually from 110 to 1200 kV (alternating current).
The force used in overhead lines to power all railway locomotives ranges from 12 kV to 50 kV (alternating current) or from 1.5 kV to 3 kV (direct current).
Galvani Potential
Inside a conductive material, the energy of an electron is affected not only by average capabilities, but also by the specific thermal and atomic medium in which it is located. When a voltmeter is connected between two different types of metal, it does not measure the difference in electrostatic potential.
The value measured with a voltmeter is negative and is usually called the voltage difference. While the pure uncorrected electrostatic capability (unmeasured by a voltmeter) is sometimes called Galvanic. The terms “voltage” and “electric potential” are ambiguous in the sense that in practice they can refer to any of them in different contexts.