2. Quadrupoles and multidipoles

2.1 Definitions and conventions

A network with the following properties is called a quadrupole:

• it is linear;

• it contains passive elements ;

• it can contain sources linked to internal quantities;

• it does not contain independent sources or sources linked to external quantities;

• it is connected to the outside only by two pairs of terminals 1,1′ and 2,2′ (figure 12 );

• the current entering through 1 exits through 1′ and the current entering through 2 exits through 2 ′....