I had the opportunity to build a Tesla Coil for Electromagnetics II at the Air Force Academy.
Here’s the basic circuit (image from twotowers.com)
I built two capacitors out of picture frames and wired them in parallel
The primary coil was wound around a wooden frame that I built.
I wound the secondary coil around a PVC pipe with coated copper wire.
Somehow I was able to get a neon sign transformer to feed the circuit. The spark gap was just two bolts with their ends filed down to points. The emitter was just a coathanger soldiered to the end of the secondary coil.
I remember plugging it in the dorm room and the result was a loud hum, a puffball of blue and purple sparks about a foot in diameter, and an obnoxious smell (Ozone!)
I got in trouble for turning it on in the dorm room. “You should have tried it first in the lab…you could have been hurt…you could have damaged electronics around you…yadda yadda yadda….”