| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a dimmer for an illuminating lamp capable of reducing power consumption by reducing the luminance of the illuminating lamp. SOLUTION: An AC voltage to be supplied to an illuminating lamp is full wave-rectified, thereby producing a serrate wave which is varied in synchronism with a full-wave rectifying signal. Subsequently, the range of an arbitrary level between minimum and maximum levels of the serrate wave is set. If the level of the serrate wave is within the range, a rectangular wave signal in an 'L' level is generated; in contrast, if it is out of the range, a rectangular wave signal in an 'H' level is generated. Since a MOS-FET is turned on or off in response to the rectangular wave signal, the AC voltage to be supplied to the illuminating lamp has a waveform which is cut in the vicinity of a peak value, thereby reducing the luminance of the illuminating lamp by the cut amount so as to achieve dimming. The dimming of the illuminating lamp leads to reduction of power consumption, with an attendant advantage of a remarkable effect of power saving. The above-described range of the level can be appropriately changed by a level range adjuster 7, thus arbitrarily changing the dimming amount within a predetermined range.</p> |
