Current｜Glossary

This page is part of the Electrical Glossary for RF and coaxial systems.

Electric current is the flow of electric charge through a conductor or circuit. It represents the rate at which charge moves and is measured in amperes (A).

By definition, 1 ampere is the current at which 1 coulomb of charge passes a point per second (1 A = 1 C/s). In electrical circuits, current flows when a voltage is applied, following Ohm’s law (I = V/R).

Current can be classified into direct current (DC), which flows in one direction with constant magnitude, and alternating current (AC), which periodically changes direction and magnitude.

The magnitude of current is directly related to heat generation. In conductors and contacts, power loss (P = I²R) can lead to temperature rise, so allowable current and derating must be considered.

Common measurement methods include clamp meters (AC/DC) and shunt resistors combined with voltage measurement.

Understanding current is essential when designing and selecting electrical and RF components.

In RF and coaxial systems, current is closely related to heat generation, signal integrity, and connector reliability.

At high frequencies, current tends to concentrate near the surface of conductors due to the skin effect. This influences conductor materials, plating, and cable design.

Excessive current can cause heating at contact points, leading to increased insertion loss and reduced long-term reliability. Therefore, current must be evaluated together with voltage, impedance, and rated specifications when selecting RF connectors and coaxial cables.

Proper current handling is especially important in high-power or continuous operation environments, where thermal management and derating become critical design considerations.