I forgot the link: http://www.linear.com/ad/current_sense.jsp
Didier KO4BB > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Hal Murray > Sent: Friday, January 18, 2008 3:55 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Slightly OT: inexpensive USB > analog-digital converter? > > > > (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. > > There are several chips designed for measuring current on 48V > busses. I think they are just an instrumentation amplifier > with big enough resistors on the front end so that the common > range goes up to 48V. > > Alternatively, if the supply is floating, you can put the > sense resistor in the ground lead, but you still need a good > amplifier to make the signal big enough for an ADC. > > > -- > These are my opinions, not necessarily my employer's. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.516 / Virus Database: 269.19.2/1223 - Release > Date: 1/13/2008 8:23 PM > > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.2/1223 - Release Date: 1/13/2008 8:23 PM _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.