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DC Power measurements up to 20V at ~30W?

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#1 chuckb

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Posted 09 December 2012 - 02:32 PM

I'd like to measure power (U3-LV AIN streaming) consumed from a 20VDC supply at up to ~30W (1.5A). The specific application here is a laptop computer's demand drawn from its 120VAC->20VDC adapter. I could certainly design my own custom conditioning board or custom LJTick for this purpose (Hall Effect or Rshunt + amp, V-divider, etc), but I'm wondering if there are already "best-known methods" for doing something like this simply/cheaply with off-the-shelf components or modules. Nirvana would be some existing module that: * Can run off of the +5V VS supply from Labjack * Current sense that outputs single-ended voltage < +3.6V (appropriate for FIO analog input) I've read some of the older threads (circa 2008) in these forums, but nothing seems to fit the bill. Ideas anyone? Thanks!

#2 LabJack Support

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Posted 10 December 2012 - 03:25 PM

For the voltage measurement consider a custom LJTick-Divider-UNI29V:


For the current measurement, a hall-effect sensor is the way to go:




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