| 摘要 |
<p>The voltage converter (29, 30, 31), which is supplied from a battery (34), for the power supply of a flashlight unit is automatically disconnected by means of a time control circuit (10 to 17) if the flash unit has not been used for several minutes. In this time control circuit, an integrated capacitor (11) is connected in parallel with the base-collector junction of a transistor (10) whose emitter is connected to the one terminal and whose collector is connected via a resistor (16) to the other terminal, of the power supply. A slowly rising voltage can be picked off on the collector of the transistor (10), which voltage causes the converter (29, 30, 31) to be disconnected when a predetermined threshold value is reached. <IMAGE></p> |
