Recent from talks
Litz wire
Knowledge base stats:
Talk channels stats:
Members stats:
Litz wire
Litz wire is a particular type of multistrand wire or cable used in electronics to carry alternating current (AC) at radio frequencies. The wire is designed to reduce losses due to the skin effect and proximity effect at frequencies up to about 1 MHz.
It consists of many thin wire strands, individually insulated and twisted or woven together, following one of several carefully prescribed patterns[better source needed] often involving several levels of bundling (already-twisted wires are twisted together into small bundles, which are then twisted into larger bundles, etc.). The result of these winding patterns is to equalize the proportion of the overall length over which each strand is at the outside of the conductor. This has the effect of distributing the current equally among the wire strands, reducing the impedance.
Litz wire is used in high-Q inductors for radio transmitters and receivers operating at low frequencies, induction heating equipment, and switching power supplies.
The term litz wire originates from Litzendraht (coll. Litze), German for 'braided/stranded wire' or 'woven wire'.[better source needed]
The skin effect and proximity effect cause conductors to exhibit higher resistance to alternating current (AC) than to direct current (DC). Due to the dual inverse nature of the electromagnetic field, the skin effect dominates at frequencies less than about 2 MHz; at higher frequencies, the proximity effect becomes the dominant force, and Litz wire induces more DC losses than solid wire or tube conductors.
The resistance of a conductor depends on its cross-sectional area; a conductor with a larger area has a lower resistance for a given length. However at high frequencies, alternating current (AC) does not penetrate deeply into conductors due to eddy currents induced in the material; it tends to flow near the surface. This is the skin effect. Therefore, in a solid conductor like a wire, current tends to flow primarily in a layer or annulus at the surface, and less current flows through the material near the center of the wire. Since less of the cross-sectional area of the wire is being used, the resistance of the wire is greater than it is for direct current (DC). The higher the frequency of the current, the smaller the depth to which the current penetrates, and the current is "crowded" into an increasingly smaller cross-sectional area along the surface, so the AC resistance of wire increases with frequency.
The depth to which AC current penetrates in a conductor is determined by a parameter called the skin depth, which is the depth at which the current is reduced to 1/e ≈ 37% of its surface value. The skin depth decreases with frequency. At low frequencies, where the skin depth is larger than the diameter of the wire, the skin effect is negligible and the current distribution and resistance are virtually the same as in DC. As the frequency rises and the skin depth gets smaller than the wire diameter, skin effect becomes significant, the current is increasingly concentrated near the surface, and the resistance per unit length of the wire increases above its DC value. Some examples of skin depth in copper wire at different frequencies are:
Round conductors such as wire larger than a few skin depths do not conduct much current near their axes, so the metal located at the central part of the wire is not used effectively.
Hub AI
Litz wire AI simulator
(@Litz wire_simulator)
Litz wire
Litz wire is a particular type of multistrand wire or cable used in electronics to carry alternating current (AC) at radio frequencies. The wire is designed to reduce losses due to the skin effect and proximity effect at frequencies up to about 1 MHz.
It consists of many thin wire strands, individually insulated and twisted or woven together, following one of several carefully prescribed patterns[better source needed] often involving several levels of bundling (already-twisted wires are twisted together into small bundles, which are then twisted into larger bundles, etc.). The result of these winding patterns is to equalize the proportion of the overall length over which each strand is at the outside of the conductor. This has the effect of distributing the current equally among the wire strands, reducing the impedance.
Litz wire is used in high-Q inductors for radio transmitters and receivers operating at low frequencies, induction heating equipment, and switching power supplies.
The term litz wire originates from Litzendraht (coll. Litze), German for 'braided/stranded wire' or 'woven wire'.[better source needed]
The skin effect and proximity effect cause conductors to exhibit higher resistance to alternating current (AC) than to direct current (DC). Due to the dual inverse nature of the electromagnetic field, the skin effect dominates at frequencies less than about 2 MHz; at higher frequencies, the proximity effect becomes the dominant force, and Litz wire induces more DC losses than solid wire or tube conductors.
The resistance of a conductor depends on its cross-sectional area; a conductor with a larger area has a lower resistance for a given length. However at high frequencies, alternating current (AC) does not penetrate deeply into conductors due to eddy currents induced in the material; it tends to flow near the surface. This is the skin effect. Therefore, in a solid conductor like a wire, current tends to flow primarily in a layer or annulus at the surface, and less current flows through the material near the center of the wire. Since less of the cross-sectional area of the wire is being used, the resistance of the wire is greater than it is for direct current (DC). The higher the frequency of the current, the smaller the depth to which the current penetrates, and the current is "crowded" into an increasingly smaller cross-sectional area along the surface, so the AC resistance of wire increases with frequency.
The depth to which AC current penetrates in a conductor is determined by a parameter called the skin depth, which is the depth at which the current is reduced to 1/e ≈ 37% of its surface value. The skin depth decreases with frequency. At low frequencies, where the skin depth is larger than the diameter of the wire, the skin effect is negligible and the current distribution and resistance are virtually the same as in DC. As the frequency rises and the skin depth gets smaller than the wire diameter, skin effect becomes significant, the current is increasingly concentrated near the surface, and the resistance per unit length of the wire increases above its DC value. Some examples of skin depth in copper wire at different frequencies are:
Round conductors such as wire larger than a few skin depths do not conduct much current near their axes, so the metal located at the central part of the wire is not used effectively.
Recent media