Analog plasma cutters, typically requiring more than 2 kilowatts, use a heavy mains frequency transformer. Inverter plasma cutters rectify the mains voltage into DC, which is fed into either an IGBT or a MOSFET. IGBT transistors operate independently of one another whilst MOSFET transistors need to be paralleled. With paralleled MOSFET transistors if one of the transistors activates prematurely it can lead to a cascading failure of one quarter of the inverter. IGBT transistors do not have this problem as they are independent however are very expensive to manufacture and generally used in high current machines where it is not possible to parallel sufficient MOSFET transistors. The transistors are switched at thousands of Hertz, which greatly reduces the magnetic flux in the step down transformer, and therefore the size of the transformer is reduced accordingly. The switch mode topology is referred to as a dual transistor off-line forward converter.

The Pilot Arc type uses a two cycle approach to producing plasma. First, a high-voltage, low current circuit is used to initialize a very small high intensity spark within the torch body, thereby generating a small pocket of plasma gas. This is referred to as the pilot arc. The pilot arc has a return electrical path built into the torch head. The pilot arc will maintain until it is brought into proximity of the workpiece where it ignites the main plasma cutting arc. Plasma arcs are extremely hot and are in the range of 15,000 degrees Celsius.

especially those without power factor correction, cannot be run from a generator. However newer models have internal circuitry that allow units withour power factor correct to run on generators.