| 摘要 |
PURPOSE:To make the brightness of an incandescent lamp constant by furnishing a specific dimmer circuit, monitoring the source voltage, and adjusting the duty ratio with respect to variation in voltage. CONSTITUTION:A dimmer circuit 3 having a triangle wave generator circuit 31 and a duty control circuit 32 is furnished, wherein the last named circuit has a comparator to decide the duty ratio for switching a transistor Q connected between the power supply 1 and an incandescent lamp 4. thereby in a car battery, for ex., the brightness of incandescent lamp 4 can be held constant within the supply voltage range which does not cause obstruction in normal car running or idling. |
