A Professional Precision Current Adapter for Multimeters.
The only low cost industry solution for multimeter burden voltage and nanoamp level current measurement.
The uCurrent™ is the only commercially available solution to the problem of burden voltage on a multimeter. See the article below to see why this little known problem can be a real big issue, even with your “precision” 0.05% Fluke multimeter. It also turns your multimeter into a powerful and precise nanoamp level measurement tool!
Thousands are in use all around the world, and it has quickly become the industry standard low cost tool for low power current measurement in modern low power microcontroller based digital electronics.
The µCurrent™ GOLD is the latest design with greatly improved specs over the original. Improvements have been made in basic accuracy, bandwidth (now you can measure fast changing “sleep” modes), current handling, and an added shorting mode to ensure uninterrupted power to your device under test while changing ranges. The µCurrent can rival 5 1/2 digit multimeters in accuracy, it is truly a precision instrument.
For increased battery life and greater potential output voltage swing, 3 x AAA batteries in series can be used instead of the coin cell. No modifications are required, just wire in parallel with the existing coin cell holder. A 3 x AAA holder fits in the existing box.
As published in the April 2009 issue of Silicon Chip Magazine.
Specifications – µCurrent™ GOLD
- 3 Current ranges:
- +/- 0-1250mA (20µV / mA burden voltage typical) * switch contact resistance plays a role here. 10uV due to the shunt resistor.
- +/- 0-1250µA (10µV / uA burden voltage)
- +/- 0-1250nA (10µV / nA burden voltage)
- NOTE: Higher currents are available by increasing the battery voltage, to a maximum of 5.5V, which would give +/-2250mA/2250µA/2250nA maximum)
- Output Voltage Units:
- NOTE: You simply read your mV multimeter range as if it were mA/µA/nA
- Resolution (nA range): 100pA (3.5digit meter), 10pA (4.5 digit meter), 1pA (5.5 digit meter)
- Accuracy (typical): <+/-0.05% on µA and nA ranges, <+/-0.1% on mA range.
- Output Offset Voltage: <50µV (essentially insignificant on 4.5 digit meter)
- Bandwidth: >300KHz (-3dB)
- Temperature Drift: <10ppm / degC (µA/nA), <15ppm / degC (mA)
- Noise: < -90dBV
- THD: < -60dB
- Battery: CR2032 Lithium coin cell (optional 3 x AAA’s)
- Battery Life: >50 hours (battery good LED ensures accurate measurement when LED is on). 2.65V cutout voltage.
PLEASE NOTE: Due to need to keep the burden voltage low, overload protection is NOT INCLUDED in the design. That means NO FUSES. Care is required in using the unit to prevent overloads.
Read the FULL ARTICLE (Description, Design, How it Works, Parts List, Testing etc, as published in Silicon Chip magazine) NOTE: This is the old design.
View the SCHEMATIC
View the BOM
Download the original Gerber, Altium PCB and Schematic files HERE.
NOTE: The old model is now discontinued.
The new model is currently only available through the Kickstarter campaign. General sales won’t be available again until around March 2014.
- 3 Current ranges: