Structure and function A threepart circuit design comprising a singlestage filter, a common mode filter, and a twostage filter circuit. This is a passive filter device built from inductive and capacitive components to compensate DC harmonics. Harmonics and power quality Filters out single or multiple harmonics in the power supply to purify the DC power rail. Improves the quality and stability of DC power by reducing ripple and harmonic content. Common mode protection Includes a common mode filtering stage to suppress fast transient interferences. Targets interference occurring at repetition rates of several kilohertz at specified points in the system. Key benefits Enhances reliability and performance of DCpowered equipment by delivering cleaner, more stable power. Passive, lowmaintenance design with no active power requirements. Simple integration into existing DC power architectures using standard LC components. Robust hardware suitable for systems where harmonic suppression and transient noise reduction are important. Compatibility and performance notes Designed to operate as part of DC power supply paths, providing targeted harmonic suppression and transient noise reduction. The threestage arrangement balances filtering effectiveness with a straightforward, passive implementation. Use scenarios Industrial automation and control panels: clean the DC bus powering sensors, actuators, and controllers to reduce noiseinduced errors and improve reliability. Telecom and data center equipment: purify DC rails in power distribution and UPS architectures to enhance signal integrity and equipment uptime. Laboratory instrumentation and test benches: provide a stable, lownoise DC supply for precision measurements and experiments.