[time-nuts] Slightly OT: inexpensive USB analog-digital converter?
John Ackermann N8UR
jra at febo.com
Fri Jan 18 08:22:13 EST 2008
Hal Murray wrote:
>> (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.
Fortunately the power supplies in question already have analog voltage
and current metering, so I should be able to just tap into the existing
shunt resistors, though I may need to do some calibration and scaling.
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