Top loads form the capacitor for the secondary
circuit. Along with the secondary coil they form a resonant circuit at the same
frequency as the primary circuit.
As the secondary inductor is so large (500-2500 turns) and the primary inductor is so small (2-10 turns), the secondary capacitance can be small (8-100pf)
As the secondary inductor is so large (500-2500 turns) and the primary inductor is so small (2-10 turns), the secondary capacitance can be small (8-100pf)
Any lump of metal will form a capaticance, but
to allow as much energy to be stored in the topload with out the power "breaking
out" the topload needs to be as smooth as possible. Any sharp point will
accumulate electrical charge and discharge to the atmosphere.
The most common shape of topload is the torroid, but spheres and other shapes are also used.
The most common shape of topload is the torroid, but spheres and other shapes are also used.
|
Spherical |
 |
Torroidal |
 |
Multiple Torrids |
 |
Torroid made from aluminium ducting |