Connectors, switches, relays and terminal blocks. The physical hardware that links a system together.
The network passes static checks and communicates for hours at idle. Direction changes produce short bursts of errors on the longest branch. Where should the investigation begin?
The catalogue number is usually tied to a temperature-rise test. Contact loading, wire size, ambient temperature and ageing decide what the connector can carry in the real assembly.
The MOSFET substitution is explained before a fictional field-reliability problem involving low-level signals and repeated vibration.
