Thanks, I've look around but could not find one that uses Gnd and Vcc instead of +/- Vcc. Is there any common and popular rail-to-rail opamp (including those +/-Vcc ones)? Thanks >From: Tom Messenger >Reply-To: pic microcontroller discussion list >To: PICLIST@MITVMA.MIT.EDU >Subject: Re: [EE]: Voltage Un-Follower Op-Amp >Date: Sat, 17 May 2003 20:44:41 -0700 > >At 03:31 AM 5/18/03 +0000, you wrote: > >Hi, > > > >I have configured my op-amp LM324 as a voltage follower by typing the >-ve > >input to the output of 1 op-amp gate. When I tie the +ve input to ground, > >the output is 0v. But when I tie the +ve input to Vcc(same as the +5v >supply > >to the LM324), the output is just 3.8v. Is there something I missed out? > >Maybe. >Get the data sheet. >Look at the specification for "output range" or "output swing". > >Lm324's positive output swing will go to around 1.5 Volts less than the >positive rail. If you need your buffer to go "rail-to-rail", then look for >a CMOS op-amp with rail-to-rail output swing. There are many available >these days. > > > > >Thanks Mark > >No problem >Tom M. > >-- >http://www.piclist.com hint: PICList Posts must start with ONE topic: >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics