Some Problems in Relay Circuit Design

In the design of sequential relay circuits one often has to consider the circuit as a part of a larger system, and one must take into account the nature of the inputs to the circuit. Frequently, the inputs are two-terminal contact networks with one terminal grounded; such inputs will be called simple. This paper examines the formal design techniques as applied to circuits with simple inputs. It is shown that all relays should be considered as secondary, from the point of view of both races and minimization. Several other shortcomings of the present theory are pointed out. Properties of circuits with simple inputs are examined. It is shown that there are flow tables not realizable without races with simple inputs, and that the presently known secondary assignment methods are not applicable to circuits with simple inputs.