Inductance of Circular Loop
[file: circular.mcd]
Formulas included in this spreadsheet:
-
Inductance of circular wire loop LCIRC()
-
Impedance magnitude of inductor at one frequency
XLF()
-
Impedance magnitude of inductor as seen by rising
edge XLR()
Variables used:
Inductance of wire loop (H):
 A loop
of 24-gauge wire the size of the loop between your thumb and forefinger
has about 100 nH of inductance.
 Changing
the wire diameter from AWG 24 to AWG 14 makes little difference. The log
function is rather insensitive to wire size.
Impedance magnitude of inductor at frequency f (W):
l Inductance (H)
f Frequency (Hz)
The impedance, at 100 MHz, of a 100-nH inductor is 62
W.
Impedance magnitude of inductor as seen by rising
edge (W):
l Inductance (H)
tr 10-90% rise time (s)
The impedance, as seen by a 5-ns rising edge, of a
100-nH inductor is 62 W.
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