Here is what the output discharge of Aron's Solid State Tesla Coil looks like. A beautiful, hissing, HOT display of HVRF. When the coil is in tune, (achievable by just turning a front-panel mounted pot!) the arcs are super-straight and swordlike in appearance. When slightly out-of-tune, the discharge gets shorter in length, but "bushier" - something that looks more like a flame. Anyhow, if you reach toward these arcs and try to touch them, they will "fold" back into the discharge terminal as your hand gets closer. There is no output when your hand is closer than 2 inches! This is because your hand acts as a capacitance to ground, lowering the frequency of the secondary circuit, and therefore throwing the system out-of-tune. This is one of the most fascinating electronics projects for me to ever come across. SSTC's feature an extremely unique combination of high voltage, RF energy, century-old Tesla technology, and sensitive electronics. They are very difficult to make reliable. The two words Tesla and electronics only mix in a perfectly designed system!