Abstract: In addition to comprising swivel arms (15) carrying magnetic heads (4), a swivel member (12) seated rotationally movable in a rotational positioner for a magnetic disc storage comprises carrier arms (14) carrying a movable element (16) of a magnetic drive system. A latch means that only releases the swivel member in the operating condition of the disc storage comprises a retainer element (23) radially projecting from the swivel member and also comprises a latch element (19). In the simplest case, this can be fashioned as a leaf spring that engages behind the retainer element when the swivel member enters into a predetermined latched position. For releasing the retainer element, a bipolar enable pulse (v) is supplied to the magnetic drive system (9, 10, 16), this enable pulse first moving the swivel member from the release position beyond the latched position, thereby disengaging the latch means and then moving past the disengaged latch element into the released position with maximum acceleration.

Abstract: Optical wand for automatic character recognition including a scanner unit designed to be a manually movable along a line of print of a data carrier in order to recognize optical characters and incorporating a light source for illuminating a scanning window and a sensing device. A second scanner unit includes a second sensing device and is designed for recognizing bar code marks. A gun shaped housing forms a common case for both scanner units.

Abstract: A circuit arrangement contains an oscillator for producing high frequency pulses, a gate circuit, a pulse transformer and a triac. The high frequency pulses can be connected to the primary winding of the transformer by way of the gate circuit. The secondary winding of the transformer is connected in the control circuit of the triac. The line voltage load is connected in the output circuit of the triac. A switch is arranged at the output of the gate circuit and is connected to the primary winding of the transformer. The switch is closed only during the presence of one polarity of the pulses so that a current can only flow through the primary winding of the transformer during a corresponding interval.

Abstract: A circuit arrangement for monitoring the phase sequence of a rotary field includes a voltage comparator which is provided and which receives one half-waves from two phases and the other half-wave of a third phase is fed, inverted, to its first input in order to form a measuring voltage and a non-inverted half-wave is fed to a second input as a reference voltage. The voltage comparator is adjusted so that it emits an error signal which characterizes an erroneous phase sequence when the reference voltage exceeds the measuring voltage.

Abstract: A circuit arrangement for producing a regulated high dc voltage from three-phase current utilizes a three-phase current bridge rectifier which is connected to lines for the three phases of the three-phase current, and a first circuit having a transistor is arranged parallel to the three-phase current bridge rectifier circuit and includes a base for receiving a control current. In each line of a three-phase supply, a series resistance is connected in front of the connection points of the lines of the three-phase current bridge rectifier.

Abstract: A circuit arrangement for inexpensive production of three-phase current from dc current contains two dc voltage sources connected in series, the connection point of which is selected as reference voltage. A chopper circuit is provided which is arranged in parallel to the series circuit of the dc voltage sources and which produces two ac voltages phase-displaced by 60.degree. from the dc current provided by the dc voltage sources.