Inductance of excited coil?

[Robin Marks]

Is there any way to calculate the inductance of an AC excited coil?

The specific setup involves a 20T bifilar wound 30mm diameter air core
coil. One winding applies a low frequency square wave to stimulate
emissions from a reagent placed within the coil. The second winding is
capacitively tuned prior to a high gain amp. Hence the need to know
the inductance.

Thank you for your reply.

Robin

 

[Reg Edwards]

To calculate coil inductance it is necessary to know length and
diameter of the former and number of turns.

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[Winfield Hill]

Robin Marks wrote...

Is there any way to calculate the inductance of an AC excited coil?

The specific setup involves a 20T bifilar wound 30mm diameter air core
coil. One winding applies a low frequency square wave to stimulate
emissions from a reagent placed within the coil. The second winding
is capacitively tuned prior to a high gain amp. Hence the need to
know the inductance.

The common Wheeler equation should apply just fine, although you're
expected to know the length of the coil. The bifilar winding will
be very tightly coupled, so whatever is connected to it can strongly
affect your tuned pickup coil (low-capacitance current-source drive
should work well, without influencing the tuning). Also, the coils
will have a high capacitive coupling, further complicating analysis.


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Thanks,
- Win

 

[Reg Edwards]

The common Wheeler equation should apply just fine, although you're
expected to know the length of the coil.

Indeed, to calculate the inductance, the coil length of a solenoidal
winding coil is essential.

The closeness of coupling between the primary and bifilar winding may
be enough to render the bifilar winding unnecessary. I don't think
the designer knows exactly what he is doing. Capacitance between the
turns will disappear if one winding vanishes.
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Reg.