Use a voltage divider which will give you a 25.5 to 5 volt reduction - this makes it much easier to translate the A2D reading into volts - it also gives you some headroom for "over voltages". I've used voltage dividers without any problems before for measuring Automotive voltages. You could use a precision potentiometer of around 10k as I do with the center tap going to the pic, one end going to ground and the other to the 0-15v input to be measured. I usually put a series resistor inline between the pot and the pic just to limit the input current and limit the risk of frying the pic if >5v is presented to one of the input pins. ----- Original Message ----- From: "Steve Kosmerchock" To: Sent: Monday, March 24, 2003 4:25 PM Subject: [EE]: 0 to 15V on PIC A/D line. > Friends, > I am doing a project where I will need to monitor an A/D voltage that can range from 0 to 15V. I have never tried this before but was thinking of doing something like a voltage divider going into an op-amp. Have any of you tried this before? I would love to hear from someone that has done this, what op-amps, and gotchas ... etc. Or if anybody has done it a better way I would love to hear from you. > This is my first post since leaving awhile back, so I am using YAHOO. If it is in a format (HTML) other than plain text I apologize. I looked but couldn't find a way to control it. > Thanks in advance for your time. > Steven Kosmerchock > steevn.geo@yahoo.com > > > > > > --------------------------------- > Do you Yahoo!? > Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! > > -- > 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 PICList is archived three different ways. See http://www.piclist.com/#archives for details.