BNC Connector

BNC connectors exist in 50 and 75 ohm versions. Originally all were 50 Ohm and were used with cables of other impedences, the small mismatch being negligible for lower frequencies. The 75 ohm types can be recognized by the reduced or absent dielectric in the mating ends. The different version are designed to mate with each other,[1] although the impedance mismatch will lead to signal reflections. Typically, they are specified for use at frequencies up to 4 and 2 GHz, respectively