Abstract: An A/D converter has inverting elements and delay elements alternately disposed in series. Each inverting element receives an analog voltage signal as a power source and converts a pulse signal in an inversion operation time depending on the analog voltage signal. Each delay element delays transmission of the pulse signal. The transmission of the pulse signal is started from a starting inverting element at a start time, and a transit position of the pulse signal is detected at a detection time later than the start time by a predetermined time. A digital value indicating a level of the analog voltage signal is determined from the detected transit position of the pulse signal. Because transmission of the pulse signal is delayed by the delay elements, the transit position depending on the analog voltage signal can be correctly detected.

Abstract: A pressure sensor includes a pressure detecting chamber sectionally formed by a diaphragm for receiving measured pressure and a semiconductor chip having a diaphragm as a pressure-sensitive portion is equipped in the pressure detecting chamber. Electrically insulating pressure transmitting liquid for transmitting the measured pressure received by the diaphragm to the semiconductor chip is sealingly filled in the pressure detecting chamber. Also, an electrical circuit for signal processing is equipped around the pressure-sensitive portion at the surface site of the semiconductor chip. The electrical circuit is coated by protection film. Electrical conducting film set to ground potential is formed as the uppermost layer of the semiconductor chip on the surface of the protection film.

Abstract: An infrared gas detector includes an infrared light source emitting infrared light of a specific wavelength, an infrared sensor detecting the infrared light from the infrared light source, and a gas cell accommodating the infrared light source and the infrared sensor. The infrared light source contains an LED or a semiconductor laser. Since the wavelength of the infrared light from the infrared light source is specific, the energy efficiency is high. The LED and the semiconductor laser are small devices, and therefore, the infrared light source and the infrared sensor are easily accommodated in the same small package.

Abstract: A reference voltage circuit includes an operational amplifier, a first fixed resistance resistor, a second fixed resistance resistor, a third fixed resistance resistor, a first diode and a second diode. The reference voltage circuit further includes a fourth fixed resistance resistor having an end connected to a non-inverting input terminal of the operational amplifier and the other end connected to the first diode. The reference voltage circuit is characterized by a value of the resistance of the fourth resistor being less than the resistance of the first resistor and a temperature coefficient of the fourth resistor being greater than any of the temperature coefficients of the first, second and third resistors.

Abstract: An N-type epitaxial layer is formed on a p-type silicon substrate. Four N+ regions (diffusion regions used as electrodes) are formed in the N-type epitaxial layer. An insulation layer having a fixed depth is formed around each of the N+ regions on a principal surface of an epitaxial layer. The insulation layer restricts a current path region formed between the N+ regions. Side surfaces of the N+ regions are covered by the insulation layer. The N+ regions are brought into contact with the epitaxial layer by a bottom surface exposed from the insulation layer.

Abstract: A sensor includes a sensing portion for sensing physical quantity, a connector portion integrated with the sensing portion for electrically connecting the sensing portion and an outer circuit outside the sensor, a sensor casing for accommodating the sensing portion, and a connector casing for accommodating the connector portion. Both the sensor casing and the connector casing are made of thermoplastic resin. The sensor casing has a predetermined portion exposed outside from the connector casing. The other portion of the sensor casing is covered with the connector casing.

Abstract: Detecting the rotational direction of a rotor is feasible by allowing a constant current source to supply a constant current flowing from an electric potential supply line to the earth in response to a turning-on action of a switch. Accordingly, detecting both the rotational speed and the rotational direction of the rotor is feasible by using three wiring cables of a power source line, an earth line, and a signal line outputting a pulse signal in accordance with the rotation of the gear. Using such a one-stage voltage adjustment enables the detection signal processing circuit to reduce electric power consumption compared with a system requiring a two-stage voltage adjustment.

Abstract: A rotation angle sensor including a variable capacitor and a C-V converting circuit, wherein the variable capacitor has a detected object fastened and fixed to its shaft, a planar shape of a movable electrode is set so that an area of overlapping parts of electrodes changes linearly with respect to a change of the rotation angle of the movable electrode, a voltage signal of the C-V converting circuit corresponds to the change of the electrostatic capacity of the variable capacitor with respect to the fixed capacitor, and consequently the voltage signal of the C-V converting circuit (detection signal) can be made to change linearly with respect to broad changes of the rotation angle of the detected object (0° to 270°).

Abstract: A pressure sensor includes a pressure detecting chamber sectionally formed by a diaphragm for receiving measured pressure and a semiconductor chip having a diaphragm as a pressure-sensitive portion is equipped in the pressure detecting chamber. Electrically insulating pressure transmitting liquid for transmitting the measured pressure received by the diaphragm to the semiconductor chip is sealingly filled in the pressure detecting chamber. Also, an electrical circuit for signal processing is equipped around the pressure-sensitive portion at the surface site of the semiconductor chip. The electrical circuit is coated by protection film. Electrical conducting film set to ground potential is formed as the uppermost layer of the semiconductor chip on the surface of the protection film.

Abstract: Physical quantity detection equipment includes a detector, an amplifier, an offset adjustment device, an addition device, and an output device. The detector outputs the first voltage corresponding to the detected physical quantity. The amplifier amplifies the first voltage. The offset adjustment device determines a measurement range of the amplified first voltage and outputs a second voltage corresponding to the determined measurement range. The addition device subtracts the second voltage from the amplified first voltage. The output device outputs the subtracted amplified first voltage and informs the determined measurement range. The equipment has only one sensing unit for detecting both a large and a fine change in physical quantity.

Abstract: First and second predetermined charging voltages are applied between the movable and fixed electrodes of a capacitive type of sensor to measure first and second capacitances between the movable and fixed electrodes, respectively. The first and second electrostatic capacitances are compared to obtain a characteristic of the sensor from a result of comparison. In measuring the first and second capacitances, first and second charging voltages are generated of which magnitudes are determined in accordance with the first and second capacitances, respectively. Equalization is made between the first output voltage when the first charging voltage is applied between the movable and fixed electrodes in a predetermined normal condition of the movable electrode and the second output voltage outputted when the second charging voltage is applied between the movable and fixed electrodes in the predetermined normal condition.

Abstract: A magnetic sensor apparatus has a ring circuit constructed with an odd number of semiconductor magnetic sensors connected in a ring shape. The drain regions of each magnetic sensor are separated from each other, so that currents flowing into the drain regions vary corresponding to the magnitude of the applied magnetic field. The semiconductor magnetic sensors function as inverters and inverting operations thereof cause time delay variable with the magnetic field strength. Digital data indicating a propagation condition of a pulse signal within the ring circuit correspond to the magnetic field.

Abstract: A sensor includes a sensing portion for sensing physical quantity, a connector portion integrated with the sensing portion for electrically connecting the sensing portion and an outer circuit outside the sensor, a sensor casing for accommodating the sensing portion, and a connector casing for accommodating the connector portion. Both the sensor casing and the connector casing are made of thermoplastic resin. The sensor casing has a predetermined portion exposed outside from the connector casing. The other portion of the sensor casing is covered with the connector casing.

Abstract: In a capacitive sensor apparatus, a capacitive sensor includes a plurality of physical-quantity-detection capacitors each having a movable electrode and a fixed electrode. A conversion device operates for converting an output signal of the capacitive sensor into an apparatus output signal. Each of the physical-quantity-detection capacitors is selectively connected and disconnected to and from the conversion device. A determination is made as to whether or not each of the physical-quantity-detection capacitors fails in response to the sensor output signal. When it is determined that a first one of the physical-quantity-detection capacitors fails, the first one is disconnected from the conversion device and a second one of the physical-quantity-detection capacitors is connected to the conversion device.

Abstract: A pressure sensor device (1) includes a sensing element (2) for sending an analog signal according to pressure. The pressure sensor device (1) outputs the analog voltage to a microcomputer (20) through an input-output terminal (8). An input-output control circuit (4) monitors the voltage value in the input-output terminal (8). When the voltage of the input-output terminal (8) is set to high by the microcomputer (20) and is dislocated from a predetermined range, the input-output control circuit (4) functionally changes the input-output terminal (8) outputting a detecting signal to a terminal for inputting an external signal from the microcomputer. After the input-output terminal (8) is changed to the terminal for inputting the external signal, a range control circuit (7) fetches an external command signal through the input-output terminal (8) and switches the output characteristics.

Abstract: Physical quantity detection equipment includes a detector, an amplifier, an offset adjustment device, an addition device, and an output device. The detector outputs the first voltage corresponding to the detected physical quantity. The amplifier amplifies the first voltage. The offset adjustment device determines a measurement range of the amplified first voltage and outputs a second voltage corresponding to the determined measurement range. The addition device subtracts the second voltage from the amplified first voltage. The output device outputs the subtracted amplified first voltage and informs the determined measurement range. The equipment has only one sensing unit for detecting both a large and a fine change in physical quantity.

Abstract: A magnetic sensor apparatus has a ring circuit constructed with an odd number of semiconductor magnetic sensors connected in a ring shape. The drain regions of each magnetic sensor are separated from each other, so that currents flowing into the drain regions vary corresponding to the magnitude of the applied magnetic field. The semiconductor magnetic sensors function as inverters and inverting operations thereof cause time delay variable with the magnetic field strength. Digital data indicating a propagation condition of a pulse signal within the ring circuit correspond to the magnetic field.

Abstract: First and second predetermined charging voltages are applied between the movable and fixed electrodes of a capacitive type of sensor to measure first and second capacitances between the movable and fixed electrodes, respectively. The first and second electrostatic capacitances are compared to obtain a characteristic of the sensor from a result of comparison. In measuring the first and second capacitances, first and second charging voltages are generated of which magnitudes are determined in accordance with the first and second capacitances, respectively. Equalization is made between the first output voltage when the first charging voltage is applied between the movable and fixed electrodes in a predetermined normal condition of the movable electrode and the second output voltage outputted when the second charging voltage is applied between the movable and fixed electrodes in the predetermined normal condition.

Abstract: In a capacitive sensor apparatus, a capacitive sensor includes a plurality of physical-quantity-detection capacitors each having a movable electrode and a fixed electrode. A conversion device operates for converting an output signal of the capacitive sensor into an apparatus output signal. Each of the physical-quantity-detection capacitors is selectively connected and disconnected to and from the conversion device. A determination is made as to whether or not each of the physical-quantity-detection capacitors fails in response to the sensor output signal. When it is determined that first one of the physical-quantity-detection capacitors fails, the first one is disconnected from the conversion device and second one of the physical-quantity-detection capacitors is connected to the conversion device.

Abstract: A semiconductor pressure sensor in which a semiconductor sensor element is contained in a package which is made by assembling a first case and a second case, and which have simple structure with low cost. The semiconductor pressure sensor is generally made up of a sensor element made of semiconductor; a sensor case made of resin; plural leads insert-formed into the sensor case so as to be partly exposed from the sensor case, wherein the leads is electrically connected to the sensor element; and a connector case assembled with the sensor case for covering the sensor element. The connector case has a flange portion which is provided with a cover portion, and a surround portion protruding from the cover portion for surrounding an exposed portion of the leads. The surround portion and the exposed portion form a connecting portion which can be connected with an external terminal. Hence, connecting function of the sensor can be realized with simple structure without additional connecting members.