Abstract: A semiconductor laser driving circuit has a semiconductor laser for emitting a laser beam according to a drive power. A photodetector is provided for effecting photo-electric conversion of the laser beam to output a corresponding electric signal. A monitoring circuit is connected for monitoring the electric signal to output a monitor signal indicative of variation in intensity of the laser beam. A controlling circuit is connected for comparing the monitor signal with a given reference signal to output a control signal according to difference therebetween. A powering circuit is operative according to the control signal to apply to the semiconductor laser a drive power effective to eliminate the difference. An abnormality detecting circuit is provided for comparing the monitor signal with a given limit signal which is set different from the reference signal to detect abnormality to output an abnormality signal.

Abstract: A stepper motor in which the end portions of each of a pair of conductors are connected to their corresponding terminal processing units arranged in one array in the circumferential direction outside of stator units. The terminal processing units are integral with bobbins on which the conductor is wound in the stepper motor.

Abstract: A tape drive of the type for withdrawing a magnetic tape together with a leader block connected to the leading end thereof out of a tape cartridge so as to record and reproduce the information onto or off of said magnetic tape. In addition to driving sources for driving a supply reel disposed in the tape cartridge and a take-up reel, a single power source is provided for accomplishing the opening or closing of a door of the housing, the vertical movement of the housing, the displacement of the leader block and the pushing or ejection of the tape cartridge out of the housing.

Abstract: A disk cartridge shutter opening and closing mechanism which is disclosed herein is designed to open and close a shutter of a disk cartridge having a variety of disks contained in a shuttered hard case and is of a construction having a pair of arms swingably mounted within a range of a width of the disk cartridge, the arm having a block which is pivotally mounted on its leading end and integrally formed with an engage head portion and an arm portion which are used for opening and closing of the shutter. The pushing-in of the disk cartridge causes the pair of arms to be swung toward each other, thereby opening and closing the shutter. A smaller pushing-in force enables the shutter to be smoothly opened and closed. Moreover, the whole mechanism is thin and compact.

Abstract: A drive and control circuit for laser diodes includes: a first switching element connected in series to a laser diode connected to a constant-current source for actuating the laser diode when a binary drive signal is at one level thereof; an impedance element connected in parallel to the series circuit of the laser diode and the first switching element, the impedance element being connected to receive the constant-current source together with the laser diode and having impedance characteristics substantially equal to those of the laser diode and the constant-current source; an integrator circuit for integrating the data at the one level; an impedance control circuit for variably controlling the impedance of the impedance element in response to the integrator circuit; and a second switching element connected in series to the impedance element for actuating the impedance element when the drive signal is at the other level.

Abstract: An electronic calculator with a time display function which is operable in either a calculator mode, a clock mode or a world clock mode is disclosed. The calculator includes a calculator section for performing basic arithmetic calculations. An input unit is provided for supplying input data and country codes to the calculator section and a time unit signal generator is provided for supplying a time unit signal to the calculator section. The calculator section includes an arithmetic part for carrying out at least the four basic arithmetic calculations; a memory part for storing the output of the arithmetic part, a control part for controlling the arithmetic part and the memory part, and a common display for displaying the contents of the memory.