Tesla’s “hairpin circuit” produces cold electricity using radiant energy. Cold electricity is what Eric Dollard would call a pure dielectric field and is also produced in a properly constructed and tuned Tesla coil. It is constructed with a spark gap or other disruptive/polarizing device and capacitors to the other part of the circuit which is only connected through capacitors. Extremely high voltages and frequencies are perfectly safe to handle in this circuit. The circuit or even loads can be shorted and continue to work. Loads only need to be connected by one wire. Power consumption decreases when a load is applied due to radiant energy. Radiant energy is produced generally by a high voltage capacitive discharge that is interrupted.
The first video is a demonstration of the original circuit using one wire for connecting the load.
The next video demonstrates how this type of electricity is harmless and a solid state design.
The last video is a schematic with an explanation of effects and includes analysis including a scope. Also he explains that current is only moving fast in the load.
The link is more information including Tesla’s original lectures which describes this technology extensively.