electrical current

(noun)

the movement of charge through a circuit

Related Terms

Examples of electrical current in the following topics:

  • Current and Voltage Measurements in Circuits

    • The electrical current is directly proportional to the voltage applied and inversely related to the resistance in a circuit.
    • An electrical circuit is a type of network that has a closed loop, which provides a return path for the current.
    • According to Ohm's law, The electrical current I, or movement of charge, that flows through most substances is directly proportional to the voltage V applied to it.
    • The electric property that impedes current (crudely similar to friction and air resistance) is called resistance R.
    • Describe the relationship between the electrical current, voltage, and resistance in a circuit

  • Solenoids, Current Loops, and Electromagnets

    • In physics, the term solenoid refers to a long, thin loop of wire, often wrapped around a metallic core; it produces a magnetic field when an electric current is passed through it.
    • Early in the 19th century, it was discovered that electrical currents cause magnetic effects.
    • Electromagnetism is the use of electric current to make magnets.
    • An electromagnet creates magnetism with an electric current.
    • In later sections we explore this more quantitatively, finding the strength and direction of magnetic fields created by various currents.

  • Conductors and Insulators

    • This flow of charge is electric current.
    • Insulators are materials in which the internal charge cannot flow freely, and thus cannot conduct electric current to an appreciable degree when exposed to an electric field.
    • Just as conductors are used to carry electrical current through wires, insulators are commonly used as coating for the wires.
    • When exposed to enough voltage, an insulator will experience what is known as electrical breakdown, in which current suddenly spikes through the material as it becomes a conductor.
    • The copper allows current to flow through the wire, while the polyethylene ensures that the current does not escape.

  • Overview of Electric Current

    • Electric current is the flow of electric charge and resistance is the opposition to that flow.
    • The firing of neurons in your brain is also an example of electric current - that is, the movement of electric charge through a conductive medium.
    • In equation form, electric current I is defined to be
    • A useful and practical way to learn about electric current and resistance is to study circuits .
    • Unlike static electricity, where a conductor in equilibrium cannot have an electric field in it, conductors carrying a current have an electric field and are not in static equilibrium.

  • Different Types of Currents

    • An electrical circuit is an interconnection of electrical elements that has a closed loop giving a return path for the current.
    • Direct current (DC) is the unidirectional flow of electric charge.
    • The electric potential and current may also be labeled at various points of the circuit .
    • A brief introduction to electric circuits and current flow for introductory physics students.
    • Describe structure of an electrical circuit and identify elements of a direct current circuit

  • Humans and Electric Hazards

    • The hazards from electricity can be categorized into thermal and shock hazards.
    • A shock hazard occurs when electric current passes through a person.
    • Electric shock occurs upon contact of a body part with any source of electricity that causes a sufficient current through the skin, muscles, or hair.
    • Frequency: Very high-frequency electric current causes tissue burning but does not penetrate the body far enough to cause cardiac arrest.
    • An electric current can cause muscular contractions with varying effects.

  • Maxwell's Equations

    • Fundamentally, they describe how electric charges and currents create electric and magnetic fields, and how they affect each other.
    • Ampere's law originally stated that magnetic field could be created by electrical current.
    • Maxwell added a second source of magnetic fields in his correction: a changing electric field (or flux), which would induce a magnetic field even in the absence of an electrical current.
    • He named the changing electric field "displacement current."
    • The microscopic approach to the Maxwell-corrected Ampere's law relates magnetic field (B) to current density (J, or current per unit cross sectional area) and the time-partial derivative of electric field (E):

  • The Hall Effect

    • When current runs through a wire exposed to a magnetic field a potential is produced across the conductor that is transverse to the current.
    • The Hall effect is the phenomenon in which a voltage difference (called the Hall voltage) is produced across an electrical conductor, transverse to the conductor's electric current when a magnetic field perpendicular to the conductor's current is applied.
    • Thus, an electric potential is created so long as the charge flows.
    • The Hall coefficient (RH) is a characteristic of a conductor's material, and is defined as the ratio of induced electric field (Ey) to the product of current density (jx) and applied magnetic field (B):
    • Eventually, when electrons accumulate in excess on the left side and are in deficit on the right, an electric field ξy is created.

  • Sources of EMF

    • Electromotive force, also called EMF (denoted and measured in volts) refers to voltage generated by a battery or by the magnetic force according to Faraday's Law of Induction, which states that a time varying magnetic field will induce an electric current.
    • By separating positive and negative charges, electric potential difference is produced, generating an electric field.
    • The created electrical potential difference drives current flow if a circuit is attached to the source of EMF.
    • When current flows, however, the voltage across the terminals of the source of EMF is no longer the open-circuit value, due to voltage drops inside the device due to its internal resistance.
    • If a load is attached, this voltage can drive a current.

  • Electric vs. Magnetic Forces

    • It should be emphasized that the electric force F acts parallel to the electric field E.
    • The curl of the electric force is zero, i.e.:
    • A consequence of this is that the electric field may do work and a charge in a pure electric field will follow the tangent of an electric field line.
    • The electric field is directed tangent to the field lines.
    • A magnetic field may also be generated by a current with the field lines envisioned as concentric circles around the current-carrying wire.The magnetic force at any point in this case can be determined with the right hand rule, and will be perpendicular to both the current and the magnetic field.