Johtosäiettä

Johtosäiettä refers to a Finnish term that translates to "conductor filament" or "leader strand." In the context of electrical engineering and materials science, it generally describes a single, thin strand of conductive material, often metal, that is part of a larger conductive structure like a wire or cable. These individual filaments are typically twisted or braided together to form a more flexible and robust conductor than a solid wire of equivalent cross-sectional area.

The use of multiple fine filaments instead of a single solid core offers several advantages. Flexibility is a primary benefit, allowing conductors to bend repeatedly without breaking. This is crucial in applications involving moving parts or tight spaces. Additionally, for alternating current (AC) applications, the "skin effect" causes current to flow more on the surface of a conductor. Using multiple smaller filaments can, in some cases, reduce the overall resistance compared to a solid conductor of the same diameter, though this effect is highly dependent on frequency and conductor geometry.

Common materials used for johtosäiettä include copper and aluminum, due to their excellent electrical conductivity and malleability. These filaments are manufactured through processes like drawing, where metal is pulled through a die to reduce its diameter. The precise diameter and number of filaments in a conductor are important design considerations that influence its overall electrical resistance, current-carrying capacity, and mechanical properties.