| 摘要 |
PURPOSE:To enable lighting by a battery having electromotive force lower than forward voltage to forward currents required for lighting a LED by mounting the LED constituting a series circuit together with a coil on the opening of a switch element and a DC-DC converter, which receives the feed of the battery and voltage thereof is boosted and supplies a control circuit with electricity. CONSTITUTION:When a transistor 4 is brought to the state in which it is opened as a switch element-that is, it is at OFF, an infrared LED 3 and a coil 6 constitute a series circuit in the direction that forward currents flow by the self- electromotive force of the coil 6. On the other hand, a DC-DC converter 7 receives feed from a dry cell 1a, is boosted to voltage required for operating a control circuit 2, and supplies the control circuit 2 with electricity. The switch element 4 is switched by the control circuit 2, and the currents of the coil flowing during the closing of the switch element flow through the LED when the switch element is opened, thus light-emitting the LED. Accordingly, the battery having electromotive force smaller than forward voltage necessary for lighting the LED can be used, thus miniaturizing the device. |
