Abstract :
Relay counting circuits to meet conventional requirements are considered. If only one relay is allowed to move at the start and at the finish of each input pulse, it is shown that the minimum total number of relays is required. The sequence of states of the circuit can thus be characterized by a cyclic permuted code, this term being used in a more general sense than is customary. Circuits using the reflected binary cyclic permuted code are given, and means of adapting them so that the number of states in the counting cycle is not restricted to be a power of two. These have the disadvantage (shared by most relay counters) of different relays wearing at different rates. Basically different cyclic permuted codes are given, for the particular cases of four digits and five digits, resulting in more even wear. No code with this property has been found, however, which applies to any number of digits.
