
General product design 301
expected component characteristics between each node can be derived from the circuit
schematic, using a component parameter library.
An in-circuit tester carries out an electrical test on each component, to verify its
behaviour, value and orientation, by applying voltages to nodes that connect to each
component and measuring the resulting current. Interactions with other components are
prevented by guarding or back-driving. The technique is successful for discrete
components but less so for integrated circuits, whose behaviour cannot be described in
terms of simple electrical characteristics. It is therefore most widely ...