Author Topic: AWG differential voltages, sinking current?  (Read 766 times)

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Offline HendriXMLTopic starter

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AWG differential voltages, sinking current?
« on: May 29, 2019, 10:32:16 am »
I tried to use the 2 channels of a SDG1032X, in combined mode to do a offset, just to keep the output of the first in the high resolution range of a MM. however it seems that the combining is not done on the analog side.

https://www.siglentamerica.com/operating-tip/generating-complex-waveforms-using-siglents-combine-function-x-series-dual-channel-generators/

However like using a poor mans differential probe, the AWG has also a differential between the 2 non-ground BNC connections. Using this differential, one channel will be sourcing, one will be sinking current. The question is, are they designed to also sink current?

I already have a work around thought out, like if the sinking channel, sources a 50 ohm resistor, that resistor can do the “sinking”, that will work fine with small currents.
But I’m still curious whether technically such a work around is needed. (In general, not only in the case of the small burden of the MM)

Looking at method 1 of the link one would say is is possible. It’s like having a HiZ load, and have the outputs divide the voltage between them sinking and sourcing maximal. So I think no resistor is needed :-+
« Last Edit: May 29, 2019, 10:44:31 am by HendriXML »
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Offline David Hess

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Re: AWG differential voltages, sinking current?
« Reply #1 on: May 29, 2019, 09:37:35 pm »
Each channel can sink current just fine but just because you use them as a differential output does not mean they are floating relative to ground.
 

Offline HendriXMLTopic starter

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Re: AWG differential voltages, sinking current?
« Reply #2 on: May 29, 2019, 10:25:10 pm »
Each channel can sink current just fine but just because you use them as a differential output does not mean they are floating relative to ground.
It’s only to create a (calibration) mapping with a (ungrounded) MM.
https://www.eevblog.com/forum/testgear/using-a-awg-and-a-scope-do-a-low-voltage-level-characterization-of-a-1n4005/msg2444139/#msg2444139
I understand that doing measurements with a scope or a circuit that is grounded this won’t work.

But it’s good to know, that no resistor is required.
« Last Edit: May 29, 2019, 10:29:33 pm by HendriXML »
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