| 摘要 |
<p>PURPOSE:To permit the use of a titled device also as an ordinary automatic dimming flash device other than the exclusive use by so constituting the same that a control circuit for quantity of light operates in spite of an open or short circuit state of a terminal to be supplied with electric signals. CONSTITUTION:For example, if a terminal A is open without using an exclusive camera, the output of an operational amplifier 19 goes zero, and a voltage comparator 15 emits an output signal of a high level. The voltage obtained by dividing a high level output signal with resistances 13, 14 is supplied to the inversion input terminal of another voltage comparator 10. Therefore, when the terminal voltage of an integrating capacitor 11 attains the voltage value divided by the resistances 13, 14 on account of the photocurrent flowing through a photosensor 9, the light emission operation of a flash discharge tube 6 is controlled by a light quantity control part 7. With such constitution, a control circuit for quantity of light is operatable, although the terminal A is open. Hence, this is usable both as an exclusive automatic dimming flash device and as an ordinary automatic dimming flash device other than for the exclusive use.</p> |
