Choosing Oscilloscope for Measuring Current

[Madhav Aggarwal]

Hello,

We are developing a wearable device with NRF52 as a Beacon with CR2032 coin cell battery. We need to measure current profile for the beacon and calculate corresponding battery life. For this we also referred to  Measuring current chapter in the nRF52 DK documentation. Now, in order to measure current profile as described in documentation, we are looking forward to purchase a digital oscilloscope with following configuration:

Hantek 6022BE: Bandwidth: 20MHz; Sample Rate: 48MSa/s; Vertical Resolution: 8bit

Can you please confirm whether it would serve our purpose as we are tight on budget to purchase expensive one. Or, maybe you can suggest some cheap alternative to it.

Thank you,

Madhav

[haakonsh]

48Msps is more than enough. 

I suggest you read some reviews of the HW and SW before buying. 

[Madhav Aggarwal]

According to AmbystomaLabs, 48MSa/s is pretty slow which is quite contrary to what you suggested. Can you please clarify?

[haakonsh]

For an oscilloscope it's quite slow, but it's more than enough to capture the current consumption waveforms of low powered devices. I think the size of the internal memory buffer is more important with regards to current consumption measurements. 

At 48Msps and 1Ms of memory you've got 1 second/48 = 20.8ms capture window. You will often want to trade sample rate for longer capture window, so a higher sample rate is not always better. 

What is the maximum sample rate that you can stream via USB with this device? 

[Madhav Aggarwal]

Thank you for providing a deeper insight. It can operate at 48MSa/s rate via USB 2.0. Is 20.8ms capture window sufficient for our purpose? 

[AmbystomaLabs]

Since we are talking about buffer size, the Rigol has a 12Mpt buffer vs. the Hantek has only 1Mpt.  So, for the same sweep settings the Rigol will have a 250mSec capture window vs. the Hantek's 20.8mSec,  Yep, over 10 times bigger.

Based on web reviews the Hantek seems to be popular with automobile mechanics.  If you are determined to have a USB device,  there are very good USB o-scopes out there, much better than the Hantek.  I would choose a dedicated device though, with its own monitor.

[Madhav Aggarwal]

AmbystomaLabs,haakonsh you for your replies. It has made our decision easier.