A first resistor and a second resistor are coupled in series between a voltage source and an active load. When the current drawn by the active load exceeds a current threshold corresponding to a maximum admissible voltage drop across the first resistor, a stabilization current is delivered to the node common to the series coupled first and second resistors in such a way as to stabilize the voltage on the terminals of the active load at a threshold value. In the presence of such a current in excess of the current threshold, the current consumed by the active load is measured from the voltage drop across the second resistor. Conversely, if the current is less than the current threshold, the current consumed by the active load is measured from the voltage drop across the first resistor.

An autoranging ammeter with fast dynamic response allows improved dynamic measurement of rapidly changing direct electrical currents. The ammeter utilizes a low-cost dual threshold comparator mechanism coupled with an analog-to-digital converter and digital processing to rapidly select the appropriate current shunt resistor.

A current sensor includes a first resistor between a first node and a second node, a first voltage limiting device between the first node and the second node, and a second resistor between the second node and a third node, wherein a resistance level of the first resistor is greater than a resistance level of the second resistor, and wherein a current flowing from the third node to the first node is configured to be measured based on a voltage across the first resistor or a voltage across the second resistor.

A current sensor includes a first resistor between a first node and a second node, a first voltage limiting device between the first node and the second node, and a second resistor between the second node and a third node, wherein a resistance level of the first resistor is greater than a resistance level of the second resistor, and wherein a current flowing from the third node to the first node is configured to be measured based on a voltage across the first resistor or a voltage across the second resistor.

A feedback ammeter, which may be included in a source measure unit or a digital multi-meter, for example, including an operational amplifier having an input and an output and a feedback path electrically coupled between the output and the input of the operational amplifier. The feedback path includes a first non-linear device to allow the measurement of decades of current. The ammeter also includes an amplifier electrically coupled to the input of the operational amplifier and the output of the operational amplifier, a second non-linear device electrically coupled to an output of the amplifier, and a resistor electrically coupled between the second capacitor and the input of the operational amplifier. A constant resistance input impedance is established using the second non-linear device that can adjust the circuit gain.

A segment selectable signal conditioning circuit and a measurement device are provided. The circuit outputs respective voltage threshold signals through various voltage threshold sub-circuits. The voltage threshold signals are preset to have different threshold values. Each segment voltage conditioning sub-circuit conditions the input voltage signal according to the corresponding conduction signal to obtain a corresponding output voltage signal. The selection circuit receives the input voltage signal and each voltage threshold signal, and compares the voltage value of the input voltage signal to the threshold value of each voltage threshold signal respectively, and outputs the corresponding conduction signal based on the comparison result to achieve segment selectable voltage signal conditioning.

A current sensor for biomedical measurements includes: a first amplifier; a first capacitor; a second capacitor; a first switch connected in parallel with the first capacitor; a second switch connected in parallel with the second capacitor; a second amplifier; a third capacitor; a resistor; and a switched capacitor network. The first capacitor and the second capacitor are connected in series and across a first input and output of the first amplifier. The third capacitor and the resistor are respectively connected across a first input and output of the second amplifier. The switched capacitor network is connected between the output of the first amplifier and the first input of the second amplifier.

A current sensor for biomedical measurements includes: a first amplifier; a first capacitor; a second capacitor; a first switch connected in parallel with the first capacitor; a second switch connected in parallel with the second capacitor; a second amplifier; a third capacitor; a resistor; and a switched capacitor network. The first capacitor and the second capacitor are connected in series and across a first input and output of the first amplifier. The third capacitor and the resistor are respectively connected across a first input and output of the second amplifier. The switched capacitor network is connected between the output of the first amplifier and the first input of the second amplifier.

The present disclosure relates to an insulation resistance measuring device and method, including a parameter resistance connected to a negative electrode terminal of a battery; a shunt resistance connectable to the parameter resistance; a current detection circuit including an operational amplifier configured to detect and output voltage between both ends of the shunt resistance; and a control unit configured to determine the insulation resistance of the battery using a switch control terminal configured to control a switch connected between the parameter resistance and the shunt resistance to an ON or OFF state, a detection signal output terminal configured to selectively apply a first high voltage signal and a first low voltage signal to the shunt resistance, a control signal output terminal configured to apply a control voltage signal to the operational amplifier to adjust an output voltage of the operational amplifier within a predetermined range, an ADC connected to an output terminal of the operational amplifier, and a predefined insulation resistance formula that includes, as a parameter, a first voltage change amount with respect to the output voltage of the operational amplifier being measured through the ADC when the first high voltage signal and the first low voltage signal are applied to the shunt resistance.

A device inspection apparatus according to one aspect of the present disclosure includes a voltage source configured to apply a voltage to a device to be inspected, a plurality of resistors connected in series between the voltage source and the device, a detector configured to detect a potential difference across both ends of a resistor group that includes one or more resistors among the plurality of resistors, a switching device configured to switch the resistor group from which the detector detects the potential difference among the plurality of resistors, and a controller, wherein the controller is configured to control the detector and the switching device, so as to detect a potential difference across both ends of at least two or more different resistor groups, and is configured to control the detector and the switching device to detect the potential difference in an ascending order of a combined resistance value between both ends of the at least two or more resistor groups.