| 摘要 |
A simplified control circuit for a single stroke electrical tool comprises a first triggerable gate connected in series with the tool across a source of supply. A series circuit including a second gate, a trigger capacitor, and a manually actuated switch is then connected between a trigger terminal and a current terminal of the first gate. A silicon controlled rectifier pulse generating circuit supplies synchronizing pulses of one polarity to the second gate and charging current of the opposite polarity to the trigger capacitor. Positive feedback from the trigger terminal of the first gate to the input of the second gate gives improved triggering sensitivity and renders the circuit relatively insensitive to changes in the value of components. Multiple firing is prevented by connecting a resistor or diode between the trigger capacitor circuitry and the trigger terminal of the first gate, and by utilizing the voltage drop across the load to aid in fully discharging the trigger capacitor.
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