Practical EMI/RFI Protection with Hybrid Filter Contact Connectors

Filter connectors have been available since the mid-1960's but have only recently come "of age". Increased concern (and product sensitivity) over EMI/RFI in medical electronics, rapid transit, commercial aircraft and military applications has resulted in broad product-line availability from several manufacturers. Most filter connectors intermate and intermount with their standard equivalents. Without altering the normal function of a standard connector contact, the filter contact provides attenuation at frequencies above a prescribed point (low pass). Through the use of special ceramic and ferrite compounds, shaped, plated and located appropriately, a network approximating a Pi-section low-pass filter is achieved on any or all contacts on a standard connector. "L" and multilayer capacitive "C" filters are also in use.