Abstract: The physical quantity measurement device involves a terminal unit, a sensor, a storage unit, an output unit, a communication unit, a control unit, and a discriminating unit. The terminal unit has a power terminal, an output terminal, and a ground terminal. The communication unit uses the power terminal in order to receive a serial signal from an external device. The control unit has an adjusting mode and a normal mode. The discriminating unit decides that the external device requests either the adjusting mode or the normal mode based on whether or not an electrical potential of each of the power terminal and the output terminal satisfies a predetermined condition. The control unit selects the normal mode when the discriminating unit decides that the external device requests the normal mode, and selects the adjusting mode when the discriminating unit decides that the external device request the adjusting mode.

Abstract: An I/F converter 10 includes a first comparator portion 111, a second comparator portion 112, a current mirror circuit 14, a reference voltage source 15, an SR-type flip-flop circuit 16, a buffer amplifier 18, a first capacitive element C1, a second capacitive element C2, a switch SW1, a switch SW2, a switch SW11, and a switch SW21. The respective operational characteristics of the first comparator portion 111 and the second comparator portion 112 are identical to each other. The respective capacitance values of the two capacitive elements C1 and C2 are equal to each other. The I/F converter 10 is connected at its input end 10a to a photodiode PD, such that a current generated in the photodiode PD is inputted to the input end 10a, allowing a signal at a frequency corresponding to the amplitude of the inputted current to be outputted from the buffer amplifier 18 to the counter portion 19.

Abstract: The physical quantity measurement device involves a terminal unit, a sensor, a storage unit, an output unit, a communication unit, a control unit, and a discriminating unit. The terminal unit has a power terminal, an output terminal, and a ground terminal. The communication unit uses the power terminal in order to receive a serial signal from an external device. The control unit has an adjusting mode and a normal mode. The discriminating unit decides that the external device requests either the adjusting mode or the normal mode based on whether or not an electrical potential of each of the power terminal and the output terminal satisfies a predetermined condition. The control unit selects the normal mode when the discriminating unit decides that the external device requests the normal mode, and selects the adjusting mode when the discriminating unit decides that the external device request the adjusting mode.

Abstract: An I/F converter 10 contained in a photodetector is provided with a first comparing portion 111, a second comparing portion 112, a current mirror circuit 14, an SR type flip-flop circuit 16, a buffer amplifier 18, a first capacitor C1, a second capacitor C2, a switch SW1, a switch SW2, a switch SW11 and a switch SW21. The operation characteristics of the first comparing portion 111 and the second comparing portion 112 are identical to each other. The capacitance values of the two capacitors C1 and C2 are equal to each other. The input terminal 10a of the I/F converter 10 is connected to a photodiode, and the I/F converter 10 inputs current generated by the photodiode through the input terminal 10a thereof and outputs a signal having the frequency corresponding to the magnitude of the input current from a buffer amplifier 18.

Abstract: An I/F converter 10 contained in a photodetector is provided with a first comparing portion 111, a second comparing portion 112, a current mirror circuit 14, an SR type flip-flop circuit 16, a buffer amplifier 18, a first capacitor C1, a second capacitor C2, a switch SW1, a switch SW2, a switch SW11 and a switch SW21. The operation characteristics of the first comparing portion 111 and the second comparing portion 112 are identical to each other. The capacitance values of the two capacitors C1 and C2 are equal to each other. The input terminal 10a of the I/F converter 10 is connected to a photodiode, and the I/F converter 10 inputs current generated by the photodiode through the input terminal 10a thereof and outputs a signal having the frequency corresponding to the magnitude of the input current from a buffer amplifier 18.

Abstract: An I/F converter 10 includes a first comparator portion 111, a second comparator portion 112, a current mirror circuit 14, a reference voltage source 15, an SR-type flip-flop circuit 16, a buffer amplifier 18, a first capacitive element C1, a second capacitive element C2, a switch SW1, a switch SW2, a switch SW11, and a switch SW21. The respective operational characteristics of the first comparator portion 111 and the second comparator portion 112 are identical to each other. The respective capacitance values of the two capacitive elements C1 and C2 are equal to each other. The I/F converter 10 is connected at its input end 10a to a photodiode PD, such that a current generated in the photodiode PD is inputted to the input end 10a, allowing a signal at a frequency corresponding to the amplitude of the inputted current to be outputted from the buffer amplifier 18 to the counter portion 19.