This is a small 2"(5cm) coil I built some month ago from some scrap parts.
The secondary is by far not
perfect, there are 2 or 3 places where the wire overlaps and the lower part has experienced several primary
Nevertheless it keeps running and serves me for some experiments that I would rather not do with my
big coils. The primary cap is made up from 10 WIMA FKP1, 100nF units that are rated 650V AC / 1600V DC each.
I had tried the MKP10 type before, but the connection between the connection wire and the cap's foil is to weak to
stand the heavy discharge currents.
Power source is a 8KV, 30mA transformer and the coil employs a multi segment
static spark gap.
Primary is a helical coil made from 9 closeound turns of 1mm magnet wire. Topload is a
7cm metal sphere.