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Now available in the EU from Welectron (Germany)

What it is

The CurrentRanger turns your multimeter or oscilloscope into a precise nano/micro/milli-amp measurement instrument.
It avoids the problem of burden voltage present in most DMMs and even some expensive bench multimeters.

Important - read the Product Guide before use:

It's important to understand how to use the CurrentRanger properly or it can be damaged.
To keep cost low, there is no isolation between input, output and USB or any other header connectors.
Therefore it's crucial to understand how to use CurrentRanger properly, without creating ground loops and current paths from input to output or to USB, or it can be permanently damaged.
In a nutshell, you should never have 2 earth ground referenced circuits connected in any combination to the CurrentRanger. Read the guide safety page for details and good/bad usage examples.

If you live in the EU, avoid delays in shipping/customs and other hidden import fees, and get yours directly from Welectron!

Main highlights

  • Fully digitally controlled by a SAMD21 Cortex M0+ ARM Processor
  • Firmware available for customizations & programmable via Arduino IDE
  • Touch pads for quick manual ranging and toggling features like: autoranging, LPF, Bias
  • LiPo battery power extends battery life and yields a greater measurement range
  • Auto-power-off feature saves your battery after a period of inactivity
  • Unidirectional/Bidirectional modes allow DC/AC measurements
  • LowPassFilter feature allows smoothing scope traces for crisp detail
  • Optional OLED display to show local readings without a DMM
  • Optional Bluetooth/HC-06 serial module allows data logging to a PC

Kit components (R3)

  • CurrentRanger board
  • 4X low profile banana terminals - these are really nice, compact and cost effective, highly recommended over the bulky "GOLD" terminals
  • Thumb terminal for easy input wiring (separate, requires soldering)
  • Buzzer for audible feedback (separate, requires soldering)
  • 3D printed PLA Box and mounting screws (box also available on Thingiverse)
  • No battery is included - please see the guide for required LithiumPolymer battery specification. Compatible 2pin JST connector also available in case you have a battery with a different connector.
  • Optional SSD1306 0.96" I2C OLED Display with 1x4 female header (requires soldering) - also sold separately
  • Optional OLED Display Enclosure - also sold separately

Optional OLED Enclosure (highly recommended!)

The OLED is super useful to give you instant readings in an ultra-portable package and without any other tools required (DMM/multimeter, computer etc.). But it is quite fragile so there is an optional enclosure for it, highly recommended, protects your OLED's glass and FPC connector from accidental damage. You may also print your own since the model is freely available here. You may also purchase the OLED enclosure separately here.

Other compatible terminals

You may install your own custom type of terminals if you'd like. These are just a few examples, and are not included in the kit.
Please see photos below of how some such terminals look and feel compared to the compact terminals.
Also see some examples and customizations in this forum thread.

Plastic shielded "gold" terminals:

CurrentRanger with the kit low profile banana terminals:

CurrentRanger with both the low profile and shielded "Gold" terminals:

Other input/output connectors & customizations

The CurrentRanger was designed to allow many types of standard connectors, below are just a few examples. You may source your own custom connectors from ebay and other similar sites, to suit your needs.

Please see the CurrentRanger forum for discussions, customizations and common issues/solutions.

Sample capture of a radio packet

Here's a sample capture of an RFM69 radio packet, shown here on an oscilliscope. This was captured in the mA range where 1mV == 1mA of current.


Review by Andreas Spiess