Precise Current Detection of Current Adapters for Micro-Current Multimeters

VPG’s CSM2512 series of high-precision current sensing foil resistors have four-pin Kelvin structure, low thermal potential (EMF) and high precision, which can further improve the precision of micro-current multimeter adapters.

VPG’s CSM2512 series of high-precision current sensing foil resistors have four-pin Kelvin structure, low thermal potential (EMF) and high precision, which can further improve the precision of micro-current multimeter adapters.

Product used: CSM2512 series high precision current detection foil resistor

challenges

Configuring a professional current adapter can turn your multimeter (or oscilloscope) into a powerful and accurate current detection tool. The device can accurately measure standby and sleep currents down to nano-amps (nano-amps) and even pico-amps (pico-amps) in the latest generation of microcontroller electronics. In addition, it is a precision 100 times voltage amplifier. In order to achieve the high-precision standard, a high-precision current sense resistor with the characteristics of high precision, low thermoelectric potential and high stability is required.

Precise Current Detection of Current Adapters for Micro-Current Multimeters

Figure: PCB board of microcurrent adapter

solution

In applications requiring power, the current sense resistor is the core passive component of an analog circuit. This device measures the voltage drop that occurs when current flows through a resistor. Therefore, there are generally five issues that affect the accuracy of the measurement: connection errors, external and internal temperature errors, frequency, load stability, and thermal EMF. The CSM2512 series of high-precision current-sensing foil resistors used in this device can avoid all the above problems and fully meet the reliability requirements.

The resistor has a four-pin Kelvin structure, and a fully welded structure is used between the resistor material and the copper-plated pins. This design reduces the stress effect (TCE) between the resistor and the PCB due to solder joints and thermal expansion. The resistor itself is designed to dissipate power evenly and prevent hot spot effects. At the same time, the thermal conductivity of the resistor material and the lead material should be similar, so that the thermal electromotive force is as low as 3 μV/°C.

By using the CSM2512 series of high-precision current sensing foil resistors, the device improves the measurement accuracy by ±0.05% on the order of µA and nA, and improves the measurement accuracy by ±0.1% on the order of mA. It also improves the maximum current and load voltage in the order of mA. The bandwidth is extended to 300KHz, and the user can measure the rapidly changing current of the microcontroller in sleep mode. An additional “short-circuit mode” ensures uninterrupted power supply during the test.

The Links:   FLC26XGC6R LC171W03-A4K6