[time-nuts] Slightly OT: inexpensive USB analog-digital converter?

Poul-Henning Kamp phk at phk.freebsd.dk
Fri Jan 18 04:59:21 EST 2008

In message <20080118095515.8B26BBE34 at ip-64-139-1-69.sjc.megapath.net>, Hal Murr
ay writes:
>> (My goal is to add digital voltage and current monitoring to some
>> older bench power supplies.) 
>Measuring voltage is simple.  If the input range is too big, you need a few 
>resistors.  If it's small, you lose a few bits from the top of the A/D.  Add 
>an op-amp if you need them.
>Measuring current gets tricky.

Actually not, there are several good chips like the INA197.

Or the very simple way, buy a suitable hall-effect current monitor
like LTSR from Lem.com.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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