There's been a lot of discussion about use of the internal clamp diodes on the list. Several people discourage it. I have used them with 16c74 and 18c452 with a transformer secondary (something like 12VRMS) through a current limit resistor to the RB0/INT pin to detect zero cross of the AC line. It has served me well. Reading further on the list, I now see you're doing this on an ANALOG input. As pointed out by Dwayne Reid, this does seem to have an effect on other analog inputs. I don't recall right now what the effect was, but I think it was more of an analog multiplexor leakage problem than anything to do with the clamp diodes. Putting too high a voltage on an analog input does seem to mess up other analog inputs. I noticed this a couple years ago, so I don't recall the details. Harold On Thu, 30 May 2002 16:42:34 -0700 "Tal (Zapta)" writes: > Hello, > > Is it OK to use the internal clamp diode of the analog input of > 12F675 for > over voltage protection ? > > That is, what happens if the input is connected through a reasonable > resistor (e.g. 10K) to a > voltage of let's say 20V ? > > Thanks, > > Tal > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/web/. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu