electricity - How does increasing voltage or current affect the power? - Physics Stack Exchange
Build an intuitive understanding of current and voltage, and power. of time, it can be expressed mathematically using the following equation: electric and magnetic fields, which in turn come from the position and motion of other charges . Electric power basic formulas calculator voltage current mathematical equation formula for power law watts resistance understanding. Ohm's law is the most important, basic law of electricity. It defines the relationship between the three fundamental electrical quantities: current, voltage, and.
On the other hand, electric potential energy is more analogous to electric force in that for it to be present, there should be a subject charged particle or object which has that energy. Electric potential is often simply called potential by physicists.
Because electric potential energy is based on an arbitrary point where its value is set at as zero, the value of electric potential at a given point is also based on this same arbitrary zero point reference point where the potential is set at zero. The potential at a given point a is then the difference between potentials from point a to the zero point, often called a ground node or just ground. Calculations of electric potential energy or electric potential based on Coulomb's Law are sometimes theoretically possible, such as might be for electric field calculations, but again these are of mostly theoretical interest and not often done in practical applications.
Therefore, such calculations are also omitted here in favour of more applicable material. Often it is of interest to compare the potentials at two different points, which we may call point a and point b.
Then the electric potential difference between points a and b Vab would be defined as the electric potential at b minus the electric potential at a.
Electric potential difference is often simply called potential difference by physicists. Under direct current DC conditions and at any one instant in time under alternating current ACpotential and potential difference are numerical or scalar quantities, not vectors, and they can have positive or negative values.
Voltage[ edit ] Voltage is electric potential expressed in volts. Similarly, potential difference expressed in volts is often called voltage difference or often referred to as voltage across two points or across an electrical component. The terms electric potential, potential, and potential difference are terms more often used by physicists.
Power Law: The Relationship of Voltage, Current, and Watts - Wisc-Online OER
Since these quantities are almost always expressed in volts or some related unit such as millivoltsengineers, electricians, hobbyists, and common people usually use the term voltage instead of potential. Furthermore, in practical applications, electrical force, electric field, and electrical potential energy of charged particles are not discussed nearly as often as voltage, power, and energy in a macroscopic sense.
The following explains why voltage is "analogous" to the pressure of a fluid in a pipe although, of course, it is only an analogy, not exactly the same thingand it also explains the strange-sounding "dimensions" of voltage.
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- Relationship and Difference Between Voltage, Current and Resistance
Consider the potential energy of compressed air being pumped into a tank. The energy increases with each new increment of air.
Basic electrical quantities: current, voltage, power
Pressure is that energy divided by the volume, which we can understand intuitively. Now consider the energy of electric charge measured in coulombs being forced into a capacitor. Voltage is that energy per charge, so voltage is analogous to a pressure-like sort of forcefulness.
Also, dimensional analysis tells us that voltage "energy per charge" is charge per distance, the distance being between the plates of the capacitor. More discussion is on page 16 of "Industrial Electronics," by D.
Shanefield, Noyes Publications, Boston, Frequency[ edit ] When an electric circuit is operating in Direct Current DC mode, all voltages and voltage differences in the circuit are typically constant do not vary with time.
The number of times the period repeats or "cycles" per unit time is called the frequency of V t.
Under DC conditions or at any one instant in time under AC, potential or voltage and potential difference or voltage difference are numerical or scalar quantities, not vectors, and they can have positive or negative values.
However, in AC mode, the overall function of voltage with time V tcan be expressed as a complex number or a phasor for a given frequency. The frequency can be expressed in cycles per second or simply sec-1, which is called Hertz Hz in SI units.
Ground[ edit ] Ground is shown on electronics diagrams, but it isn't really a component.
It is simply the node which has been assigned a voltage of zero. It is represented by one of the symbols below. Technically, any single node can be assigned as ground, and other voltages are measured relative to it. However, the convention is to only assign it in one of two ways, related to the type of power supply. In a single supply situation, such as a circuit powered by a single battery, the ground point is usually defined as the more negative of the power source's terminals.
This makes all voltages in the circuit positive with respect to ground usuallyand is a common convention.
DC Circuit Theory: Voltage, Current, Resistance, Power & Ohms Law
Voltage and current are the cornerstone concepts in electricity. We will create our first mental models for these basic electrical quantities. We will also talk about power, which is what happens when voltage and current act together.
Charge The concept of electricity arises from an observation of nature. We observe a force between objects, that, like gravity, acts at a distance. The source of this force has been given the name charge.
A very noticeable thing about electric force is that it is large, far greater than the force of gravity. Unlike gravity, however, there are two types of electric charge.
Opposite types of charge attract, and like types of charge repel. Gravity has only one type: Conductors and insulators Conductors are made of atoms whose outer, or valence, electrons have relatively weak bonds to their nuclei, as shown in this fanciful image of a copper atom. When a bunch of metal atoms are together, they gladly share their outer electrons with each other, creating a "swarm" of electrons not associated with a particular nucleus.
A very small electric force can make the electron swarm move.
Electronics/Voltage, Current, and Power
Copper, gold, silver, and aluminum are good conductors. There are also poor conductors. Tungsten—a metal used for light bulb filaments—and carbon—in diamond form—are relatively poor conductors because their electrons are less prone to move. Insulators are materials whose outer electrons are tightly bound to their nuclei. Modest electric forces are not able to pull these electrons free.