A Rapper Control Circuit and Method of Control

摘要

1,153,073. Semi-conductor oscillator circuits. JOY MFG. CO. 23 Aug., 1966 [30 Sept., 1965], No. 37684/66. Heading H3T. In a circuit for controlling the actuation of a solenoid 16 which causes movement of a hammer, the solenoid control signal has a variable mark/space ratio. The control pulses are generated by charging capacitor 46 through resistor 44 until the potential across it is sufficient to cause unijunction transistor 48 to conduct switching on transistor 60 and discharging capacitor 46 through resistor 62. The resulting saw-tooth signal is fed to gate con. trolled SCR 20 which is thus switched on, to energize solenoid 16, for a period determined by resistor 62, and switched off for a period determined by resistor 44.