These devices are complete electronic circuits, consisting of discrete components sealed into boxes, which carry out specific logical and data-control functions. Circuit blocks were the first commercially available 'potted circuits', whose operation did not need to be understood in order to use them in an electronic system. They were a transitional type of device used at a time when integrated circuits, which consist of components such as transistors built into chips of silicon, were in their infancy. The use of circuit blocks and, later, integrated circuits has led to standardisation, miniaturisation and modularity of electronic system design.

Inv. 2000-320