There's other solutions to this problem too. Look at isolation amplifiers from TI(try ISO120) or Analog(try ad202 or ad210). -Denny ----- Original Message ----- From: "Michael Milner" To: Sent: Monday, December 29, 2003 3:21 PM Subject: [EE:]Analog Opto-isolation? > Hi, > > I've been using opto-isolators for some time now to isolate digital data > lines. What I was wondering is if I can use "normal" opto-isolators to > isolate an analog signal. > > I'm building a motor controller and I would like to keep the motor supply > completely separate from the digital (pic) supply (No common ground). > > I'm using a small resistor in series with the motor to generate a small > difference voltage drop proportional to the current being drawn. I'm > planning on then using a dfferential amplifier to amplify the difference > voltage and feed this into a opto-isolator. > > Will this work? Is the opto-isolator performance linear over its range? > > Thanks, > > Mike > > -- > 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 -- 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