Electrical controllers for electric welding machines; electrical controllers for use in welding processes; power supplies for welding apparatus, including for arc welding and electric arc welding; stabilised voltage power supply; high voltage power supply; low voltage power supply; welding sensors for sensing welding parameters during welding; stationary and mechanized purge equipment for protecting molten metal during welding operations, namely, devices that shield and protect a weld by monitoring and regulating oxygen; welding cameras; welding digital video recorders; electronic apparatus for non-destructive testing of welded materials