Abstract: The invention disclosed here is an anti-cycling device for high-pressure sodium lamps. A current sensor continually monitors lamp current and outputs a low voltage signal to an amplifier. When lamp current increases, indicating a starting or recycling condition, the sensor's voltage output correspondingly increases, and the amplifier responds by amplifying such output and transmitting it to a second amplifier. The latter acts as a voltage comparator and compares the first amplifier's output with a threshold level. Each time the first amplifier's output exceeds the threshold, the second amplifier outputs a trigger signal. Such signal is counted over time, and if the number of counts reaches a certain number, the counter outputs a malfunction signal to a relay that cuts off power to the lamp. An easy-to-see LED simultaneously illuminates to indicate the cycling condition and the need for lamp maintenance.

Abstract: A constant-current light sensing system employs a constant-current diode in series with the power lead to a photoconductive cell. This diode provides a substantially fixed current through the cell and enables the system to be designed such that it can make maximum use of the linear portions of the cell's output response curve, and maximum use of the range of a potentiometer's settings. The cell used in conjunction with the system is received in a housing that is easily mountable to a wall or ceiling surface by an adhesive material.

Abstract: A constant-current light sensing system employs a constant-current diode in series with the power lead to a photoconductive cell. This diode provides a substantially fixed current through the cell and enables the system to be designed such that it can make maximum use of the linear portions of the cell's output response curve, and maximum use of the range of a potentiometer's settings. The cell used in conjunction with the system is received in a housing that is easily mountable to a wall or ceiling surface by an adhesive material.