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Air
Coil Inductors
Using Any Wire Gauges (Up to AWG #8)
CWS
manufactures all types of air coils inductors, from
round diameter wires in AWG #36 to AWG#8, and rectangular sizes
of 72 mils x 182 mils and 95 mils x 182 mils. In many cases, the
windings are done using 200 deg C class wire insulation
for
high
temperature
application.
Single
layer air coil windings formula and the Q factor can be downloaded
from the following .PDF file
CALCULATION
OF AIR COIL INDUCTORS INDUCTANCE, NUMBER OF TURNS AND Q
This
formula in the above .PDF file is most accurate when the coil
length is greater than 0.67 of the radius and the frequency
is less than 10 Mhz. As the frequency goes above 10 Mhz, parasitic
capacitance causes the formula to be less accurate.
Q
changes drastically as a function of frequency. At lower frequency,
Q is good as only the DC resistance has an effect. As
the frequency increase, Q will increase up to a point when
the skin effects and the distributed capacitance begin to dominate.
Then, Q will decrease till it reached zero at self resonance
frequency.
Q
can be increase by decreasing the windings resistance ( using
heavy gauge wires), spread the windings to lower distributed
capacitance and using a iron or ferrite core to wind over to
increase the inductance.
An
Air Coil Winding chart can be downloaded from the .PDF file
below. This chart shows the air coil inductances with various
number of turns, diameter and length.
AIR
COIL WINDING CHART
See
below for examples of custom coil windings. Please call CWS for
your requirements - high quality work at a reasonable tooling
cost and low cost volume production.
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