Capacitors are incredibly simple. a pair of conductive bits, separated by some dielectric media, and you just charge up that field between them until it eventually arcs if the voltage is too high. I started looking more into what material options for dielectric exist, and how changes in dielectric strength and constant. Unfortunately while reading about capacitor dielectrics I came across a comment saying that even a small air gap between two dielectric. The calculation that killed this path of DIY capacitors for magloops was that of power dissipation inside the dielectric material. I had seen tables of “tangent loss coefficient”, but thought that *those numbers seem small. With dielectric losses understood, my choices returned to an air variable capacitor, or a vacuum variable cap. Seeing that most any size. A variable capacitor is a whose capacitance may be intentionally and repeatedly changed mechanically or electronically. Variable capacitors are often used in to set the resonance frequency, e.g. to tune a radio (therefore it is sometimes called a tuning capacitor or tuning condenser), or as a variable, e.g. for in.