| 摘要 |
<p>PURPOSE:To eliminate loss of light emission energy and to supply a specified source voltage to a photometric circuit by emission of a flash discharge tube, by obtaining the control voltage for the purpose of turning on an electronic switch circuit which controls the supply of the specified source voltage from a constant voltage power source circuit to the photometric circuit from between the gate and cathode of a main thyristor. CONSTITUTION:12 is a diode for preventing backward current, 13 is a capacitor, 14 is a resistor, 15 is a flash discharge tube having a trigger electrode 15a, 16 is a main thyristor, 17 is a resistor, 18 is a capacitor which absorbs surge together with the resistor 17, is formed by devices ranging from a variable resistor 25 up to a capacitor 33. A photometric circuit 42 is formed. The resistor 25 sets the threshold level of an integrating capacitor 31. Switching transistors (TR) 34 up to 37 form an electronic switch circuit 43. The base and emitter of the TR37 are connected to the gate and cathode of the thyristor 16 through a resistor 41. A constant voltage power source circuit 44 is formed by devices ranging from a constant voltage diode 38 up to a capacitor 40.</p> |
