Energy saving device for public lighting installations - uses clock signal derived from AC mains to accurately drive time clock used to switch lighting

摘要

The energy saving device for public lighting installations includes a timing clock circuit which is used to switch a power interface device. The accuracy and stability of the timing clock is improved by using a driving clock signal every 0.02 second. The mains signal is derived from the secondary of the transformer used to derive the power supply for the circuit, and is applied to a frequency divider circuit to reduce the mains frequency driving clock signal to the frequency required by the timer circuit. The circuit is automatically reset by holding one terminal of the divider circuit at the DC rail voltage through a resistor.