| 摘要 |
<p>PURPOSE:To reduce a time lag till a lamp is lighted by installing a control unit being parallelly connected to a brake pedal switch and imparting a preheating current to a brake lamp periodically, in this tungsten-filament type brake lamp circuit. CONSTITUTION:When a key switch 2 is turned on, an oscillator 12 generates a rectangular wave of 100Hz or so, by way of example, therefore a one-short multivibrator 13 generates a positive pulse of time width at the specified time in synchronizing with a build-up edge of this rectangular wave. Then, a transistor Tr14 in a semiconductor switch part is turned to ON only at a time when an output pulse of the one-shot multivibrator 13 exists there, and thereby the base of a transistor Tr15 is grounded and a base current flows, so this transistor Tr15 is also turned to ON. In consequence, even if a brake pedal switch 5 is off, a preheating current is fed to a brake lamp 1 and the filament is preheated, and when this switch 5 is turned to ON, the lamp is made so as to be lighted by a slight time leg.</p> |
