초록 ▼

A direct current, variable duty cycle control circuit for the manual control of the supply of power from a direct current source to a motor is disclosed including a transistor arrangement operable when enabled to couple the direct current source to the motor along with means for enabling that transi

A direct current, variable duty cycle control circuit for the manual control of the supply of power from a direct current source to a motor is disclosed including a transistor arrangement operable when enabled to couple the direct current source to the motor along with means for enabling that transistor arrangement during an operator determinable portion of each of a series of time intervals and a sensing circuit receptive to an overload condition of the transistor arrangement for disabling that transistor arrangement. The disclosed system includes an operator control member effective in a first position to prevent the energization of the motor by preventing the supply of electrical power to the control circuit, effective in a second series of positions to vary the portion of each time interval during which the motor is supplied power and effective in a third position to deliver power continuously to the motor by bypassing the transistor arrangement.

대표청구항 ▼

Circuitry for manually controlling the energy supplied from a D.C. source to a motor comprising: transistor means operable when enabled to couple the source to the motor; means for enabling the transistor means during a selectively determinable portion of each of a series of time intervals including

Circuitry for manually controlling the energy supplied from a D.C. source to a motor comprising: transistor means operable when enabled to couple the source to the motor; means for enabling the transistor means during a selectively determinable portion of each of a series of time intervals including an astable mulivibrator having a duty cycle determining resistance-capacitance network; and means for sensing an overload condition of the transistor means and for disabling the transistor means to preclude current flow therethrough in response thereto, the means for sensing effectively short-circuiting the network capacitance when the voltage drop across the transistor means exceeds a preselected value during said determinable portion of a time interval.