LowPowerLab Forum

Hardware support => CurrentRanger => Topic started by: Jason on December 09, 2018, 11:41:54 AM

Title: Comparison / Overview of the current ranger vs the µCurrent
Post by: Jason on December 09, 2018, 11:41:54 AM

Very cool video from: Andreas Spiess.

https://www.youtube.com/watch?v=HmXfyLyN38c (https://www.youtube.com/watch?v=HmXfyLyN38c)

Title: Re: Comparison / Overview of the current ranger vs the µCurrent
Post by: TomWS on December 09, 2018, 02:00:52 PM

Great  review!  Thanks for posting!  I think I'll order a Current Ranger!  Oh, wait, I already did!   ;)

Title: Re: Comparison / Overview of the current ranger vs the µCurrent
Post by: sparky on December 10, 2018, 01:07:36 PM

Kudos Jason, you helped the sales jump!

Title: Re: Comparison / Overview of the current ranger vs the µCurrent
Post by: Bakyt on February 12, 2019, 05:46:35 AM

It is a great video! In the last minute of the video, the author says it is not advisable to use USB connection during the measurement. I could not figure out what the harm is. Does data transfer over USB affect the precision of the measurement?

Title: Re: Comparison / Overview of the current ranger vs the µCurrent
Post by: Felix on February 12, 2019, 09:54:18 AM

Bakyt,
The USB ground is not the same as the ground of the input or output. If you have non-floating (ie non-isolated) equipment hooked up at the output, that shares common earth/ground with the USB then there would be a ground loop through the CR and it could be damaged.
Same is true for input, if you power your DUT from an earth/ground referenced power supply, and you have a PC hooked to USB (also powered from mains) and/or a mains powered scope/DMM at the output, that is also a hazard condition.

However, if you have a LAPTOP running on a battery, then there is no problem outputting via USB serial, since the laptop is completely floating with respect to the rest of the circuit.

So only 1 common ground referenced circuit is permitted to be connected to the CR at 1 time.

I explained this in the guide, but I hear questions like this again and again. Folks are hooking up batteries wrong and smoking the charger circuit - and are asking for help in this forum, is the excitement so big that users skip the guide alltogether?  :)

Title: Re: Comparison / Overview of the current ranger vs the µCurrent
Post by: Bakyt on February 12, 2019, 02:00:51 PM

Thanks, Felix!
Never thought about this! The God has saved my CR from these damages while I was doing my experiments!
I just read  your explanations and warnings (https://lowpowerlab.com/guide/currentranger/safety-and-proper-usage/)!  :-[