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In making PI detectors we often need cheap testing coil. Of course not limited only for testing uses. If all tests are as expected then we can take more “pro” and a bit more expensive coil housing.
There are different approaches to satisfy this. For quick made coils I take plastic/acrylic shallow platter or saucer for flower pots of different diameter. Such platters/saucers should have enough tab at the edge to put coil in it.
Here short photo-session that demonstrate such one approach in building 25cm (9”) round coil out of acrylic platter (so called pizza platter):
First we need to cutout lower shaft mounting ears out of platter body and bend it by hot air heating in adequate position:
To winding proper coil, which can suit to platter tab, we need windings disc. Disk on photo is made out of hard isolation plate named “Styrodur”. Wire turns are lead in zig-zag way around disc perimeter picked by toothpicks as turns lead.
Wire used here was 0.5mm in diameter (24 AWG), enameled copper plated Alu wire. To retain equilibrium between inductance an DC resistance of coil, decided for 24 turns:
After fixing coil turns using string coil is put in platter tab, poured by epoxy glue and left to hardening.
Just a little makeup and PI testing coil is finished:
Technical data:
L=290uH
Q=10
DCR=2.7E
Happy new Pi project in Happy New Year!
There are different approaches to satisfy this. For quick made coils I take plastic/acrylic shallow platter or saucer for flower pots of different diameter. Such platters/saucers should have enough tab at the edge to put coil in it.
Here short photo-session that demonstrate such one approach in building 25cm (9”) round coil out of acrylic platter (so called pizza platter):
First we need to cutout lower shaft mounting ears out of platter body and bend it by hot air heating in adequate position:
To winding proper coil, which can suit to platter tab, we need windings disc. Disk on photo is made out of hard isolation plate named “Styrodur”. Wire turns are lead in zig-zag way around disc perimeter picked by toothpicks as turns lead.
Wire used here was 0.5mm in diameter (24 AWG), enameled copper plated Alu wire. To retain equilibrium between inductance an DC resistance of coil, decided for 24 turns:
After fixing coil turns using string coil is put in platter tab, poured by epoxy glue and left to hardening.
Just a little makeup and PI testing coil is finished:
Technical data:
L=290uH
Q=10
DCR=2.7E
Happy new Pi project in Happy New Year!
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