Abstract: A bipolar semiconductor integrated circuit for driving a motor and the like wherein a semiconductor pattern and a circuit are so contrived that an erroneous operation will not take place even when a negative potential is applied to the output terminal of the circuit. When a negative potential is applied, there exists a quantitative proportional relationship between a parasitic current of a parasitic transistor and a ratio of the lengths of the collectors. The parasitic current decreases with a decrease in the length of the collector. Therefore, the short side of a transistor in the control circuit is directed to the output transistor to which a negative potential will be applied. By detecting the parasitic current and by adding a current to the constant-current using a current mirror circuit, furthermore, erroneous operation due to parasitism can be completely prevented.

Abstract: An electronic circuit device decreases dispersion in the output of the circuit caused by changes in the resistance of the resistors resulting from stress. Resistor positions are selected on the circuit board so that a change in the circuit output caused by a change in resistance of a first resistor group becomes equal to a change caused by a change in resistance caused by a second resistor group, these changes being in opposite directions so as to cancel each other. Alternately, a plurality of resistors are connected to form a composite resistor such that the effect upon resistance of the composite resistor caused by the resistor having decreased resistance is cancelled by the effect upon resistance of the composite resistor caused by a resistor having an increased resistance.

Abstract: An input signal processing apparatus for use in a comparator which compares an input signal with a reference voltage signal to output a signal inverted in accordance with a comparison result. The apparatus detects the frequency of an input signal from a rotation detecting device such as pickup coil so that a mask time is set in accordance with the detected input signal frequency. The apparatus separates the levels of the input signal and a reference signal to the comparator for the mask time. The mask time is set so as to vary with a first predetermined rate of change when the input signal frequency is below a predetermined frequency and vary with a second predetermined rate of change greater than the first predetermined rate of change when the input signal frequency is above the predetermined frequency. This arrangement can appropriately set the mask time whereby it is possible to prevent the phase shift in waveshaping when the frequency of the input signal is high.

Abstract: A driving apparatus used for an analog indicating instrument having a pair of cross coils comprises a pulse signal generating device for generating a pulse signal having a frequency proportional to a quantity to be measured, a frequency-voltage conversion device for generating a ripple voltage proportional to the frequency of the pulse, holding a mean voltage of the ripple voltage as an analog voltage while restraining the ripple, and controlling the analog voltage so as to change following a mean value of the ripple voltage, thereby to supply the analog voltage, and driving devices for supplying a current in accordance with the analog voltage to the cross coils so as to drive these cross coils. The driving apparatus has effects on improving responsibility of frequency-voltage conversion operation in a low frequency region and reducing the deflection of a pointer of an instrument by restraining the ripples.

Abstract: An apparatus for driving a gauge having coils in quadrature to generate a resultant magnetic field in accordance with currents applied thereto and having a pointer angularly swept by the field, the apparatus having a memory to store a first data defining a relationship between a first level, indicative of the current applied to one of the coils, and an angle of the pointer. The first level has a continous waveform varying in isoceles trapezoid form over an angle range of 0.degree. to 180.degree.. The first data varies symmetrically with the isoceles trapezoid wave at the 180.degree. pointer angle over an angle range of 180.degree. to 360.degree.. The memory is arranged to store second data defining a relationship between a second level indicative of the current applied to the other coil and the pointer angle. The second level has a continuous waveform phase shifted by 90.degree. from the continuous waveform of the first data.