4 layers

IONPAK2
m-labs/ionpak
A modern, low-cost universal controller for hot-cathode ionization vacuum gauges. (WIP)
259 parts23
Boards in 1 GitHub repository, designed in KiCad, that use the HMC1206JT500M by Stackpole Electronics (SEI) (-55℃~+125℃ 200V 250mW 500MΩ Thick Film Resistor ±5% ±500ppm/℃ 1206 Chip Resistor - Surface Mount ROHS). See how each wires it, with its parts, size, README and files; the HMC1206JT500M’s symbol, footprint and pinout are on its own page.