Sorry... I wasn't very clear on that. I need to be able to set the current within 1% of 1 uA. So 3 amps must really be 2.99999999 to 3.00000001 amps. The hardware to control the current this accuratly is being developed by someone else. The initial plan, however, calls for the current be controlled by a proportional voltage. When I starting punching in the numbers for this, I was pretty much stumped. A 24 bit DAC seems to be about the only thing precise enough. Otherwise we will need to implement the multiple range setup. Eric On Sat, 18 Oct 2003 11:54:17 +0200 "Jan-Erik Soderholm XA (TN/PAC)" wrote: > Eric Christensen wrote: > > > I'm working on a current limited power supply that must control > > current from 0 to 4 amps with 1 uA resolution with less than 1% > > error. > > > Hi. > > 1% of what ? Full scale ? Or 1% of 1uA ? > > 1% of 4A (full scale) is actualy 40000 uA !! > > Lets say you are outputing 4A, what is then the > allowed "error" (expressed in Ampere !) ? > > Jan-Erik. > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu Eric Christensen Iowa State University Computer Engineering and Computer Science Home: (515) 572-7708 Cell: (612) 202-9336 echris@iastate.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu