A strain sensor is based on a self-biasing reference circuit that reaches an operating state that, at least at first order, is at least supply-voltage independent. The strain sensor provides an output signal that is defined by the operating state of the self-biasing reference circuit. At least one component in the self-biasing reference circuit has an electrical characteristic that depends on a strain to which the at least one component is subjected. This makes that the operating state of the self-biasing reference circuit depends on the strain. As a result, the output signal of the strain sensor varies as a function of the strain to which the at least one component is subjected.

A system includes an instrumentation amplifier (INA) including a first transistor coupled to a first input node, and a second transistor coupled to a second input node. The INA also includes a resistor coupled between the first transistor and the second transistor. The INA includes a gain resistor network coupled to the resistor and to the first and second transistors, where the gain resistor network includes two or more gain resistors. The system also includes a voltage to current converter, where the voltage to current converter is coupled to the resistor and the gain resistor network.

Provided is a weak-signal reading circuit for a sensor, comprising a sensing signal input amplifying unit and a signal reading unit. The sensing signal input amplifying unit comprises a first transistor, wherein a gate and a drain of the first transistor are connected with a sensor; the signal reading unit is connected to a source of the first transistor, the first transistor is turned on when the sensor generates a sensing signal, so that the sensing signal is captured by the signal reading unit. When the sensor senses a signal and generates a voltage, the first transistor tends to be switched on, then the signal reading unit reads the sensing signal through the first transistor which has been turned on, that is, by providing the first transistor, the weak-signal reading circuit for sensor can be self-driven according to the voltage generated by the sensor without an extra drive circuit, thereby achieving low power consumption.

The disclosure provides a gas detector with an ionizing device for producing ions depending on a gas to be detected. The gas detector includes a catcher for receiving the electrical current produced by the ions, and a measuring device with an electrical measuring resistor. The electrical measuring resistor produces an electrical measuring potential from the current and is surrounded, at least in part, by an electrical shield resistor, denoted by R.sub.T. The same potentials, up to a deviation of at most 25%, are applied in the longitudinal direction of the electrical measuring resistor to mutually opposed regions of the electrical measuring resistor and the electrical shield resistor.

The present disclosure relates to a sensor circuit including a control circuit configured to control a constant first signal to a ratiometric second signal using a first amplifier adjustable by an actuating signal, and an adjustable second amplifier for a sensor signal, the gain of which is adjustable by the actuating signal.

In one implementation, a circuit can include a reference pin and an operational amplifier that can include an output pin, an inverting input pin and a non-inverting input pin. The inverting input pin can be electrically coupled to the output pin via a first impedance and to the reference pin via a second impedance. The non-inverting input pin can be electrically coupled to the reference pin via a third impedance and can be configured to receive a detection signal. The reference pin can be configured to receive a detection reference signal associated with the detection signal.

A signal measuring apparatus and method is provided. The signal measuring apparatus inputs a reduced voltage signal to an input end of an amplifier by resetting a voltage signal, which is acquired by applying a known current signal to a target object, using a common mode voltage at least once during one period of a current signal. The signal measuring apparatus acquires a digital signal corresponding to an object impedance change by converting an output of the amplifier.

A feedback network has a feedback output terminal. A digital to analog converter has an analog output terminal. An amplifier includes an input differential pair having an inverting input terminal, a non-inverting input terminal, a first output current terminal and a second output current terminal. The inverting input terminal is coupled to the feedback output terminal, and the non-inverting input terminal is coupled to the analog output terminal. The amplifier includes a feedback differential pair having a third output current terminal, a fourth output current terminal, a first input terminal and a second input terminal. The third output current terminal is coupled to the first output current terminal, and the fourth output current terminal is coupled to the second output current terminal. The amplifier includes an amplifier output terminal coupled to the first input terminal and the second input terminal.

The present disclosure relates to chopper amplifier circuits with inherent chopper ripple suppression. Example implementations can realize a doubly utilized chopper amplifier circuit that is a current-saving circuit with a wake-up function that is capable of providing a self-wake signal in order to change into a fast, low-jitter/low-latency mode, and to provide a wake-up signal for a sleeping microprocessor or a system in response to signal changes.

A multi-loop error amplifier circuit for generating an error amplification signal includes: a first operational transconductance amplifier (OTA) including a first current output stage which generates a first transconductance amplification current in a predetermined current direction according to a first voltage difference between a positive terminal and a negative input terminal of the first OTA; a second OTA including a second current output stage which generates a second transconductance amplification current in the predetermined current direction according to a second voltage difference between a positive terminal and a negative input terminal of the second OTA. The first and the second current output stages are coupled in series to generate a first error output current. The error amplification signal is generated according to the first error output current which is equal to the smaller one of the first and the second transconductance amplification currents.