Connectors for electrical and electronic equipment - Tests and measurements - Part 23-3: Screening and filtering tests - Test 23c: Shielding effectiveness of connectors and accessories - Line injection method
This part of IEC 60512 defines a standard test method for measuring the shielding effectiveness SE of a shielded connector@ or of a connector not provided with integral shield once fitted with a shielding accessory and terminated with a screened cable. The complete assembly has a continuous 360??hielding capability throughout its length. NOTE 1 Practically@ continuous 360??hielding is not always achievable based on the geometry of the connector. NOTE 2 Shielding?? is used in this document with the same meaning as ??screening??. This test method can be applied to shielded connectors and to connector accessories with shielding capability. The following different connector designs can be tested: ?C circular connectors; ?C rectangular connectors; ?C connectors for printed boards; ?C connector shielding accessories. NOTE 3 For the definition of ??accessory?? see IEV 581-24-10. A shielding accessory i.e. an accessory that confers shielding to a non-inherently shielded connector@ may be a suitable set of shielded housings providing electrical continuity@ along the mated connector set@ between the screen of the (screened) cable at the cable outlet of the free cable connector housing and the metallic mounting surface for the fixed connector housing. The free connector housing is provided with a cable screen clamp. This test method utilizes the principle that the intrinsic shielding property of the connector/ accessory/cable assembly is its surface transfer impedance ZT which can be expressed as the longitudinal voltage inside the shield@ relative to the current flow on the outside shell. This test method is based on two impedance-matched circuits. See Figure 1 for the measurement principle. The connector specimen under test is integrated into the secondary circuit 02. The impedance-matched injection line of the primary circuit 01@ which activates the electromagnetic field@ runs parallel to the surface of the specimen under test. This test is also suitable for measuring the shielding effectiveness of a connector fitted with triaxial contacts terminated with shielded@ twisted pair cables@ as used in data bus systems. NOTE 4 This standard has been adopted by ASD-STAN (formerly known as AECMA) as EN 2591-212 .