Abstract: An indicator controller (18), an optical assembly (10) having the indicator controller (10), a traffic light system that comprises at least one of the optical assembly (10) and a method for fault indication by the indicator controller (10) is disclosed. A control signal from a control signal generator (20) of the indicator controller (18) is disabled to block off current supply to a diode chain of three light emitting diodes (LEDs) of an array (12) of LEDs. Input to the control signal generator (20) has a frequency setting section that sets the control signal at a predetermined frequency. Consequently, the three LEDs are made to blink according to the predetermined frequency. The control signal is generated when the amplitude of current supply to the array (12) exceeds a threshold setting.

Abstract: A traffic light system (10) with an impedance matching circuit (14) for electrically coupling an optical assembly (12) to a switched AC power supply (26) is described. The impedance matching circuit (14) has a matching transformer (20), a first resistor chain (22) and a second resistor chain (24). Each resistor chain (22,24) has an input and an output. Each of the inputs is common with a respective electrical node of the matching transformer (20). Each of the outputs is common with a respective supply node provided by the primary windings (18a) of an input transformer (18) of the optical assembly (12).