| 摘要 |
<p>A power saving dimming apparatus for gas discharge lamps operable through a phototransistor network (20) sensitive to the infrared spectrum. The phototransistor network (20) allows power to be supplied to the apparatus (60), resulting in the turning on of the lamps whenever daylight conditions exist which are insufficient to produce infrared light. When the power is applied to the apparatus (60), either at initial turn on or after a momentary interruption, the apparatus applies full power to the lamp ballasts by causing a switch (SCR 4 and SCR 3) to conduct continuously. A very important part of the invention being after a preselected time period determined by the clock (40) during the first two changes inthe counter (1C3) which ensures lamp ignition, the counter (1C3) in combination with the switch (SCR 3 and SCR 4) then dims the lamps at a preselected rate by progressively opening the switch (SCR 4 and SCR 5) more and more until the ultimate dimmed level is reached corresponding to the total opening of the switch (SCR 3 and SCR 4) resulting in the entire ac voltage to be applied across all the whole autotransformer (80).</p> |
