The MC34064 solve your problem? MC34064 is a brown-out circuit that output 0v when voltage is below to 4,6V. It is cheap and little circuit (a TO-92 and a resistor). What you say about it? ----- Original Message ----- From: fred jones To: PICLIST@MITVMA.MIT.EDU Sent: Thursday, April 10, 2003 11:01 AM Subject: Re: [EE]: Detecting low input voltage Hi, I'd like to ask a couple of questions and I apologize if they are "dumb" but I'm pretty weak with analog electronics. Can you explain what is meant by a softer knee? and is there a reason you used the transistor you did or could I use a 2n3906 instead? Thanks, FJ >From: Olin Lathrop >Reply-To: pic microcontroller discussion list >To: PICLIST@MITVMA.MIT.EDU >Subject: [EE]: Detecting low input voltage >Date: Thu, 10 Apr 2003 09:12:52 -0400 > >I responded to an earlier post asking how to detect low input voltage to a >LM7805 regulator, and posted a schematic with a "fancy" solution. That >was a cut and paste from another design, and I realized after hitting send >that some of the constraints in the original design don't apply to the >simple question that was asked. > >Attached is a simpler design that may be good enough for the purpose. It >has a softer knee, but that may be fine depending on the application. > >I didn't reply to my other post because it seems to have vanished into >never never land again. I probably forgot to restore the [EE]: tag that >Outlook Express stripped off the reply. Argh! I know this isn't the >list's fault, but Outlook Express is such a common email client. Is there >anything that can be done about this? > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > ><< x2.gif >> _________________________________________________________________ Tired of spam? Get advanced junk mail protection with MSN 8. http://join.msn.com/?page=features/junkmail -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.470 / Virus Database: 268 - Release Date: 08/04/03 -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body