Abstract: A drive circuit for servomotors that eliminates the need for microswitches to protect the motor when the system is driven to its limits of travel. The circuit monitors the current to the motor, identifies overload currents and terminates current flow to the motor when an overload occurs. The current flow is restored only when a reverse rotation command signal is received by the drive circuit.

Abstract: A graphics input/output device contains a graphics input pad having an array of transparent capacitive pixels the capacitance characteristics of which are changed in response to the passing of a conductive-tipped stylus over the surface of the pad. This change in capacitance is sensed by sense buffers disposed along the columns of the matrix, as the rows are scanned at a prescribed scanning rate.The sensed data is read out of the sense buffer and loaded into a RAM. An array of display pixels formed of an LCD matrix is addressed by a scan sequence control unit, and the energization of the display pixels is multiplexed with the read-out scanning of the sensed data, so as to present to the user a real time generated image of the graphics created by the stylus. As a result, it appears to the user that the stylus is actually "writing" on the display pad.