Abstract: An electrically operated stapling apparatus is disclosed having a circuit utilizing a capacitor for driving the solenoid actuator for the apparatus. The circuit includes a fullwave rectifier for charging the capacitor with closely spaced dc pulses and includes circuitry for producing a plurality of charging levels for the capacitor depending upon the number of sheet material to be stapled. A reference circuit is also provided to insure the voltage level of charging is such that the operation of the apparatus is immune to line source voltage fluctuations.

Abstract: A plurality of magnetic field generating, electrical coils are preferably arranged in a circle, in one embodiment. Digitally controlled, recurring switching pulses are generated for sequentially defining a plurality of discrete time periods. During each of these time periods, a separate magnetic field is generated responsive to each switching pulse. The pulses are applied to the coil, in turn, for sequentially stepping a magnetic field in a rotary motion about the circle of coils. In other embodiments, the pole pieces may be arranged in another geometry. For example, they could be linearly positioned to slide a stirrer or to lift a stirrer member up a test tube. A substance which is to be stirred is placed in a non-magnetic container positioned within the stepping magnetic field. A stir rod of magnetic material is placed in the container and within the stepping magnetic field, so that the stir rod couples into and rotates or otherwise moves with the rotary magnetic field.