I looked up "virutal ground" on ti.com, and found this: http://focus.ti.com/docs/prod/productfolder.jhtml?genericPartNumber=TLE2425 It is budget priced at US$0.75, and only handles 20 mA max, which would be two LEDs. I'm driving 8 so this would cost about $3.00 for enough virtual grounds. Probably out of my price range, but a really cool idea. I think I will order some samples for my next analog project, this looks like a really cool device! --Lawrence ----- Original Message ----- From: "Reginald Neale" To: "Lawrence Lile" Sent: Monday, February 04, 2002 7:30 PM Subject: Re: [PIC]: Driving a dual LED > >I understand how you would do this with an op amp - what is a "virutal > >ground" device? Part numbers? > > > >--Lawrence > > I was afraid you'd ask that. It's been a while since I looked into > it. Seems to me TI and AD both make such a device. IIRC the opamp and > dividers are integrated on-chip so you can get one in a TO-92 pkg > with only 3 terminals: V+, V-, ((V+)-(V-))/2. > > Reg > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu