kokonaisvirran

Kokonaisvirta, known in English as total current, is a term used in electrical engineering and physics to describe the net rate of charge flow through a cross-section of a conductor, circuit, or component. The form kokonaisvirran is the genitive singular, used when talking about the total current of something (for example, kokonaisvirran laskeminen means the calculation of the total current).

In circuit analysis, the total current is governed by Kirchhoff's current law (KCL): the algebraic sum of currents entering and leaving a node is zero, so the total current at a point equals the sum of the currents through the connected branches. In a series circuit, the same current flows through all components, so the total current is identical to the current in any single element. In a parallel circuit, the total current is the sum of the currents through each branch, i.e., I_total = I1 + I2 + …, assuming reference directions are consistent. In alternating current (AC) circuits, currents are typically treated as phasors, and I_total is the vector sum of branch currents, with magnitude determined by the impedances.

Measurement of total current is usually performed with an ammeter placed in series with the part of the circuit being measured. The unit of current is the ampere (A).

Applications of the concept include determining circuit behavior, power calculations (P = VI), and selecting appropriate conductors and protective devices. The term kokonaisvirta is common in Finnish educational and professional contexts, with the English equivalent being total current.