Abstract: A differential amplifier circuit generates a first current and a second current having a current difference obtained by amplifying a voltage difference between an input voltage and a reference voltage. An output stage supplies current proportional to the first current to an output node. A current conversion circuit discharges current proportional to the second current from the output node. After connecting the output node to a ground node in response to a reset signal, a latch circuit disconnects the output node from the ground node after reset cancellation. Thereafter, when voltage at the output node rises from the ground voltage in a case where a level relationship between the input voltage and the reference voltage is reversed from a reset cancellation time point, the latch circuit fixes the voltage at the output node to a power supply voltage by a positive feedback latch operation.

Abstract: A differential amplifier circuit generates a first current and a second current having a current difference obtained by amplifying a voltage difference between an input voltage and a reference voltage. An output stage supplies current proportional to the first current to an output node. A current conversion circuit discharges current proportional to the second current from the output node. After connecting the output node to a ground node in response to a reset signal, a latch circuit disconnects the output node from the ground node after reset cancellation. Thereafter, when voltage at the output node rises from the ground voltage in a case where a level relationship between the input voltage and the reference voltage is reversed from a reset cancellation time point, the latch circuit fixes the voltage at the output node to a power supply voltage by a positive feedback latch operation.

Abstract: Provided herein is a skin resistance measuring device having a simple structure and capable of accurately measuring a skin resistance. An AC voltage generated by a high-frequency power source (21) is applied to a first electrode (11). A detection circuit (30) detects a current of a second electrode (12). An inductive element (25) is provided, for example, in an electric path extending from the high-frequency power source (21) to the first electrode (11). A controller (40) changes and controls a frequency of the high-frequency power source (21), receives a detection signal (S1) from the detection circuit (30), and calculates an impedance of the human body which has touched an electrode section (10). The skin resistance of the human body is calculated based on a value of impedance at a frequency where the impedance is a minimum.

Abstract: A device for detecting an approach distance of a living body is provided. The device detects hover touch. The surfaces of a first electrode and a second electrode are covered by an insulator to form an electrode section. A high-frequency power source is connected to the first electrode via an inductive element for forming a resonance circuit. An ammeter is connected to the second electrode. A correlation between a resonance frequency and a resonance resistance is obtained. It is determined that the living body is in hover touch with the electrode section when the resonance resistance is higher than an initial resistance corresponding to a leakage resistance between the first and second electrodes, and the resonance resistance increases or decreases whereas the resonance frequency decreases or increases, based on the correlation.