It is described a leakage compensation circuit for a measurement device which comprises a measurement circuit with a leaking device that is connected to a measurement path and causes a leakage current. The leakage compensation circuit comprises: i) a replica device of the leaking device, wherein the replica device is connected to a replica path, and wherein the replica device is configured to cause a replica leakage current that is essentially equal to the leakage current of the leaking device, ii) a voltage regulator which is connected to the measurement path and to the replica path, wherein the voltage regulator is configured to regulate the voltage in the replica path based on the voltage of the measurement path, and iii) a current mirror which is connected to the measurement path and to the replica path, wherein the current mirror is configured to mirror the replica leakage current of the replica device into the measurement path.

An apparatus and method are disclosed for detecting the disconnection of a vascular access device such as a needle, cannula or catheter from a blood vessel or vascular graft segment. A pair of electrodes is placed in direct contact with fluid or blood in fluid communication with the vascular segment. In one embodiment, the electrodes are incorporated into a pair of connectors connecting arterial and venous catheters to arterial and venous tubes leading to and from an extracorporeal blood flow apparatus. Wires leading from the electrodes to a detecting circuit can be incorporated into a pair of double lumen arterial and venous tubes connecting the blood flow apparatus to the blood vessel or vascular graft. The detecting circuit is configured to provide a low-voltage alternating current signal to the electrodes to measure the electrical resistance between the electrodes, minimizing both the duration and amount of current being delivered. Detection of an increase in electrical resistance between the electrodes exceeding a pre-determined threshold value may be used to indicate a possible disconnection of the vascular access device.

An apparatus and method are disclosed for detecting the disconnection of a vascular access device such as a needle, cannula or catheter from a blood vessel or vascular graft segment. A pair of electrodes is placed in direct contact with fluid or blood in fluid communication with the vascular segment. In one embodiment, the electrodes are incorporated into a pair of connectors connecting arterial and venous catheters to arterial and venous tubes leading to and from an extracorporeal blood flow apparatus. Wires leading from the electrodes to a detecting circuit can be incorporated into a pair of double lumen arterial and venous tubes connecting the blood flow apparatus to the blood vessel or vascular graft. The detecting circuit is configured to provide a low-voltage alternating current signal to the electrodes to measure the electrical resistance between the electrodes, minimizing both the duration and amount of current being delivered. Detection of an increase in electrical resistance between the electrodes exceeding a pre-determined threshold value may be used to indicate a possible disconnection of the vascular access device.

A battery resistance diagnosis device includes a current supply unit configured to supply a preset fixed current to a battery cell, a voltage measurement unit configured to measure an open circuit voltage of the battery cell while the fixed current is supplied, an external resistance calculation unit configured to calculate an external resistance value of the battery based on the fixed current and the open circuit voltage of the battery cell, and an abnormality diagnosis unit configured to diagnose a battery abnormality due to a voltage drop by comparing the calculated external resistance value with a preset external resistance value.

A battery resistance diagnosis device includes a current supply unit configured to supply a preset fixed current to a battery cell, a voltage measurement unit configured to measure an open circuit voltage of the battery cell while the fixed current is supplied, an external resistance calculation unit configured to calculate an external resistance value of the battery based on the fixed current and the open circuit voltage of the battery cell, and an abnormality diagnosis unit configured to diagnose a battery abnormality due to a voltage drop by comparing the calculated external resistance value with a preset external resistance value.

Circuitry for characterising a test impedance of a test load, the test load coupled between a sense node and a first driver node, the circuitry comprising: driver circuitry configured to apply a time-varying test stimulus between the first driver node and a second driver node, the test stimulus varied in step changes at one or more signal events; a reference load coupled between the second driver node and the sense node, the reference load having a programmable impedance; and a first integrator configured to integrate a voltage derived from the sense node to generate a first integrated signal; and measurement circuitry configured to derive one or more characteristics of the test impedance based on the programmable impedance and the first integrated signal.

A quantum Hall resistance apparatus is to improve resistance standards and includes a substrate, a graphene epitaxially grown on the substrate and having a plurality of first contact patterns at edges of the graphene, a plurality of contacts, each including a second contact pattern and configured to connect to a corresponding first contact pattern, and a protective layer configured to protect the graphene and to increase adherence between the first contact patterns and the second contact patterns. The contacts become a superconductor at a temperature lower than or equal to a predetermined temperature and under up to a predetermined magnetic flux density.

The present application discloses a circuit and a method for detecting insulation resistance. The circuit includes: a first voltage dividing module, a second voltage dividing module, a third voltage dividing module, a fourth voltage dividing module, a first switch module, a fifth voltage dividing module, a second switch module, a third switch module, and a detecting module, where the first voltage dividing module comprises a first voltage dividing unit and a second voltage dividing unit, and the third voltage dividing module comprises a third voltage dividing unit and a fourth voltage dividing unit. According to the embodiments of the present application, errors caused by fluctuations in the pull-up of the reference power supply can be avoided, and the accuracy of the circuit for detecting insulation resistance can be effectively improved.

The present application discloses a circuit and a method for detecting insulation resistance. The circuit includes: a first voltage dividing module, a second voltage dividing module, a third voltage dividing module, a fourth voltage dividing module, a first switch module, a fifth voltage dividing module, a second switch module, a third switch module, and a detecting module, where the first voltage dividing module comprises a first voltage dividing unit and a second voltage dividing unit, and the third voltage dividing module comprises a third voltage dividing unit and a fourth voltage dividing unit. According to the embodiments of the present application, errors caused by fluctuations in the pull-up of the reference power supply can be avoided, and the accuracy of the circuit for detecting insulation resistance can be effectively improved.

Disclosed are a high-precision resistance measurement system and method combining a micro-differential method and a ratiometric method. The system includes a constant-current source, a reference resistor, a first differential amplifier, a programmable gain amplifier (PGA), an ADC, a microprocessor, a DAC and a to-be-measured resistor interface. The reference resistor and a to-be-measured resistor are connected in series between the constant-current source and ground. The voltage across the reference resistor is inputted to the first differential amplifier, and the output of the first differential amplifier is used as the reference voltage for the ADC and the DAC. The single-ended voltage to ground of the to-be-measured resistor and the output voltage of the DAC are inputted to the PGA in differential manner, and the PGA outputs the amplified difference voltage to the ADC. The output terminal of the ADC and the input terminal of the DAC are both connected to the microprocessor.