Descriptions of discrete devices specified in the form of combinational or
series circuits by means of sets of predicates are proposed. By means of se
ts of predicates it is possible to implement asynchronous simulation of the
circuits, i.e, simulate: the: circuits taking into account delays of the e
lements, using the mechanism of logical inference implemented in logical pr
ogramming Examples illustrating implementation of the proposed descriptions
of discrete devices in the Prolog language are considered.