Nominal impedance

Nominal impedance in electrical engineering and audio engineering refers to the approximate designed impedance of an electrical circuit or device. The term is applied in a number of different fields, most often being encountered in respect of:

• The nominal value of the characteristic impedance of a cable or other form of transmission line.
• The nominal value of the input, output or image impedance of a port of a network, especially a network intended for use with a transmission line, such as filters, equalisers and amplifiers.
• The nominal value of the input impedance of a radio frequency antenna