Abstract: A monitoring system for energization of traffic lamps (L 1 . . . L 8), with energy supplied from a common voltage source. Protection is provided so that energization of any one of the lamps is not in conflict with energization of another lamp. The system includes a conflict detection means (CD) having a set of inputs respectively connected to monitor individual lamps so that respective inputs of the set are activated in response to energization of respective lamps. The conflict detection means generate conflict signifying information in response to simultaneous activation of combinations of inputs. A signal group generator (SGG) feeds to the inputs a sequence of data signal groups each simultating a conflict or a non-conflict combination at the inputs. The resultant information produced by the conflict detection means (CD) is checked for correctness by a verification means under common control with the signal generator.

Abstract: A monitor circuit arrangement for traffic lights wherein energy is supplied from an alternating voltage supply source(s) to a lamp (L 1) via a controlled switch (SD 1) and energization of the unit is monitored by a voltage comparator connected in cascade with a sensing latch (SL 1). The output of the voltage comparator is activated in response to its input voltage exceeding a predetermined magnitude of either polarity relative to a common reference voltage wave. A monitored voltage representative of the voltage present across the lamp is supplied as an input voltage to the voltage comparator, the output of which is fed to the sensing latch set input. Reset means (RPS) are provided for resetting the latch at the commencement of each cycle of the alternating supply voltage.