| 摘要 |
PURPOSE:To ensure the optional setting for the change of time limit to the fluctuation factor of power supply voltage, by amplifying the fluctuation of the power supply voltage through a simple constitution. CONSTITUTION:When a power supply switch 2 is closed, the reference voltage set at a constant level is applied to the gate terminal of a PUT12. At the same time, a TR17 and a thyristor 16 are turned on and off respectively. Accordingly no current flows to a solenoid 15, and the switch 2 is kept closed with conduction to a heater 14. When the charging voltage of a capacitor 6 reaches the reference level, the PUT12 is turned on with the TR17 turned off. The current flowing to a constant voltage diode 9 flows into the gate of the thyristor 16 to turn on the thyristor 16. Then the current flows to the solenoid 15, and the switch 2 opens to discontinue the conduction to the heater 14. With the fluctuation of the power supply, the charging voltage to be applied to a CR integral network 3 becomes equal to the voltage obtained by dividing the voltage obtained by under-cutting the constant voltage VZ by resistances 19 and 20 and by the function of a constant voltage diode 18. |
