Electronic noise filtering Often, filters are required in electronics devices. They are actually in virtually every consumer device. Many locos come with a small capacitor across the motor brushes. This helps reduce electrical noise and radio interference. In some cases, like the Aristo TE system, the electronics is very sensitive to noise. Here are a few filter designs to reduce noise. I'll put in some more detail in the future. RCS systems makes some nice filters, will post pictures and link here MTH systems ***need*** DCC systems