The Primary Coil forms is the inductive part
of the primary circuit, along with the primary capacitor these two componants
form a resonant circuit.
As the primary coil handles all of the
stored power in the primary capacitance and is almost a short circut, It has to
be capable of withstanding large current pulses. For this reason it is usallly
constructed from copper tubing or heavy guage wire.
For Tuning purposes the primary coil is
tapped to allow its inductance to be changed and therefore the resonant
frequency of the primary circuit as a whole.
It is generally easier to vary the
inductance than the size of the primary capacitor.
|
Spiral wound Primary made from coper tubing Lower coupling to secondary, Smaller Inductance per turn. |
 |
Helical
wound Primary made from copper wire. High coupling, Larger inductance/turn |