Active/passive systems refer to a classification of industrial components rather than a specific brand. These systems are widely used in automation, HVAC, and energy management sectors. Active systems require external power to operate (e.g., sensors, actuators), while passive systems function without power (e.g., valves, dampers). Companies like Siemens (Germany), Honeywell (USA), and Schneider Electric (France) produce such components for industrial control and building automation. Products include motor drives, relays, and thermostats, available via distributors like Radwell and Grainger.