Measure nrf Current consumption using an Oscilloscope

[carvalhn]

Hi,

I need to measure the current consumption for nrf51DK using an Oscilloscope. I have read the user guide and they have mentioned some connectors for it. Is it possible to just measure the current consumption using an Oscilloscope and if yes, then could you please let me know how to do the same?

Thanks a lot in advance.

[Marius Heil]

Hello,

have you read the nRF51 DK Guide? It is pretty much all explained there.

First Paragraph is about measuring with a multimeter, next paragraph explains measurements with an oscilloscope.

First, cut the Solder bridge, afterwards you need to attach a resistor with 10 ohm for example on the two solder pads right next to the bridge, then you use your oscilloscope, connect both thingys (forgot what their called) to ground and the measuring tips to the two current measurement pins, just as shown in the guide. Now I've used the mathematics operations on my oscilloscope to substract the two signals and then you're ready to go.

[carvalhn]

Hi Marius,

Thanks I did about reading that actually.

I just have the following two queries:

1. After you cut the solder bridge , does it impact the functioning of the board in any way? And you can simply cut the solder bridge Or do you need to unsolder it?

2. You would need to solder the resister with 10 ohm again right? Does that impact the functioning of the board in any way?

I am just curious to know because if it doesnt impact the board, then the Nordic guys could have perhaps configured it and given it to us that way? I work with USB connections to the board. Will that have any impact in the current measurement?

Thanks and Regards, Neil Carvalho

[Øyvind Karlsen]

Hi,

1. Yes, if you do not short the solder bridge in some way, either through a resistor or a jumper, the board will not receive power. You can simply cut the solder bridge with a knife.

2. Yes you will have to solder the 10ohm resistor.

Since there are several ways to measure current(ammeter, oscilloscope, etc), that all require different measurement setups the 10ohm resistor was not included to the board.

If you have a USB connection to the board you will see a lot of noise in your measurement, try using either a battery, or preferably a power supply with current draw limit capabilities.

[carvalhn]

Hi ,

Thanks for your response.

So, it says for a ammeter I do not require a resistor fitted there. While for a Oscilloscope I do.

That means when I am normally using the device, in the case of oscilloscope it would work well. But, in case of the ammeter configuration, I will have to resolder it or something to make it work :(

Also, I have tried using the 3V battery many times but it doesnt seem to power my device at all. Any idea why?

Thanks and Regards, Neil

[Øyvind Karlsen]

Did you check the voltage of your battery?

[carvalhn]

Well not with a multimeter but its s brand new battery cr2032 3 v . I checked two of them