| 摘要 |
PURPOSE:To allow a strobe to emit light at the timing when a proper F value is obtained, by counting up a counter with pulses having a period proportional to the object distance and allowing the strobe to emit light when the counted value of the counter reaches a value which is determined in accordance with the film sensitivity. CONSTITUTION:A constant current source 3 is properly connected to an external resistance group 5 through a brush 4 to supply an output current (i) corresponding to the resistance value to an oscillator 6 in the succeeding stage. The oscillator 6 charges/discharges an external capacitor 8 by the input current (i) to generate a pulse phi having a period corresponding to the charging/discharging period, and the oscillator 6 is so adjusted that a period T of the output pulse phiis inversely proportional to the value of the input current (i) accurately. If resistance values of resistances constituting the resistance group 5 are so determined that the value of the current (i) supplied from the constant current source 3 to the oscillator 6 is inversely proportional to an object distance L accurately, the period T of the pulse phi generated by the oscillator 6 is proportional to the object distance L accurately. |
