sähkövirtaus

Sähkövirtaus, often translated as electric current, is the flow of electric charge. This charge is typically carried by electrons in a conductor, but it can also be carried by ions in electrolytes or plasmas. The direction of conventional current is defined as the direction of positive charge movement, even though in most common conductors, it is the negatively charged electrons that are actually moving.

The magnitude of electric current is measured in amperes (A), which is defined as the amount of charge passing through a cross-sectional area per unit of time. Mathematically, current (I) is expressed as I = ΔQ/Δt, where ΔQ is the amount of charge and Δt is the time interval. A more instantaneous measure is given by I = dQ/dt.

Electric current is a fundamental concept in electricity and magnetism. It is responsible for powering our homes, running our electronic devices, and enabling countless technologies. The movement of electric charges creates magnetic fields, and conversely, changing magnetic fields can induce electric currents, a principle known as electromagnetic induction.

In circuits, current flows from a region of higher electric potential to a region of lower electric potential, driven by a voltage source. The relationship between voltage, current, and resistance in a circuit is described by Ohm's Law, which states that voltage is equal to current multiplied by resistance (V = IR). Different materials offer varying degrees of opposition to the flow of current, a property known as electrical resistance.