The physics. Two knobs shape a discharge: how fast the field alternates (frequency) and how hard it pushes (voltage). Low-frequency, high-voltage AC drives large DBD reactors for ozone and surface work; short high-voltage pulses give high peak fields with low average heating, ideal for jets and delicate targets; megahertz RF at modest voltage gives the fine control prized for etching and deposition at reduced pressure. Regions are indicative operating windows for teaching, not exact device boundaries. Region positions are schematic, and this map is a first-pass screening tool only — final power-supply selection also depends on the gas, pressure, electrode gap, dielectric configuration, load capacitance, waveform, peak current, and target average power. The jet / localized-treatment mapping is for research use only; it is not a medical-device recommendation, and biomedical use requires a validated device, protocol, and applicable regulatory clearance.