Ferrite Core Coils

Created: Feb, 6 2006

Over the years I have wound and experimented with Hundreds of coils.
Many Varied Sizes and Shape.
Considerably interesting are the Small coils wound on Ferrite cores.

1) Is a PQ Core, Custom made Delrin Bobbin. Outside Diameter of this Bobbin is 1.25 inches.
"Fair-Rite" Core, Part Number "6677404021".
This coil has an Inductance of 312.6 uH.
Free Air Resonance Measures 2.06 Mhz.
The Internal Capacitance calculates to be 19 pF.
Characterics: Especially Uni-Directional with pickup at dead center.

2) Is a Pot Core, Custom made PVC Plastic Bobbin.
"Fair-Rite" Core, Part Number "5677362221".
Coil Inductance is 129.4 uH.
Free Air Resonance is 6.99 Mhz.
Internal Capacitance is 4 pF.
Characterics: Also Especially Uni-Directional, but not as sensitive as #1.

3) Is a U Core, Custom made Delrin Bobbin.
"Fair-Rite" Core, Part Number "9277015002".
In Phase Coil Inductance is 323.8 uH.
Free Air Resonance is 2.11 Mhz.
Internal Capacitance is 17.5 pF.
Characterics: Considerably Uni-Directional.
Most Sensitive at Either Pole.

4) Is a Ferrite Rod, The Coil is wound on a Custom made ABS plasic Bobbin.
The Total Length of this, Including Bobbin is 2.25 inches.
The Fair-Rite Rod is Part Number "4077375211" (3/8" Diameter X 1 15/16" Long)
Coil Inductance is 300.4 uH.
Free Air Resonance is 1.750 Mhz.
Internal Capacitance is 27.5 pF.
Characterics: Not Very Directional, but somewhat stronger to the ends than the sides.

Some of the Ferrite Coils I have made for my Detector.

Number 1 is by Far the best, Excellent for Pin-Pointing and detecting Small objects.

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