to strike his hand. Coming in contact with radio frequency arcs as shown here is extremely dangerous and can result in electrocution.
Electric currents that oscillate at radio frequencies (
RF currents) have special properties not shared by
direct current or lower
alternating current, such as the 50 or 60 Hz current used in
electrical power distribution. • Energy from RF currents in conductors can radiate into space as
electromagnetic waves (
radio waves). This is the basis of
radio technology. • RF current does not penetrate deeply into electrical conductors but tends to flow along their surfaces; this is known as the
skin effect. • RF currents applied to the body often do not cause the painful sensation and muscular contraction of
electric shock that lower frequency currents produce. This is because the current changes direction too quickly to trigger
depolarization of nerve membranes. However, this does not mean RF currents are harmless; they can cause internal injury as well as serious superficial burns called
RF burns. • RF current can
ionize air, creating a conductive path through it. This property is exploited by "high frequency" units used in electric
arc welding, which use currents at higher frequencies than power distribution uses. • Another property is the ability to appear to flow through paths that contain insulating material, like the
dielectric insulator of a
capacitor. This is because
capacitive reactance in a circuit decreases with increasing frequency. • In contrast, RF current can be blocked by a coil of wire, or even a single turn or bend in a wire. This is because the
inductive reactance of a circuit increases with increasing frequency. • When conducted by an ordinary electric cable, RF current has a tendency to reflect from discontinuities in the cable, such as connectors, and travel back down the cable toward the source, causing a condition called
standing waves. RF current may be carried efficiently over
transmission lines such as
coaxial cables. ==Frequency bands==