A vacuum tube rectifier, such as DY87 or similar HV-diode, (sorry for = european type only :-)) will actually detect radiation if it is NOT = heated. Heard about this many years ago. Don't remember if you have to = let some air inside the tube to make it work, but I don't think so. Maybe it is a bit like a Geiger tube, but far cheaper, and maybe free if = you open an old TV receiver Attila - SM4RAN -----Ursprungligt meddelande----- Fr=E5n: David VanHorn Till: PICLIST@MITVMA.MIT.EDU Datum: den 21 december 2001 19:50 =C4mne: Re: [EE]: Cheerful holiday radiation detector project >At 10:40 AM 12/21/01 -0800, Alice Campbell wrote: >>Oops, this time with topic tag :o >> >> >> For my holidays I thought I'd build a nice PIC broadband >> radiation detector. >> I've researched the web and asked around, and have = found two >> non-Geiger circuits that look promising. Both involve a = diode >> of some sort for a detector, followed by a FET-style = opamp, >> followed by an audio or comparator stage for final = output >> processing. >> >> >> My question involves the diode detector: One seems to = call >> for a 'large-area photodiode', something that I don't = offhand >> have in the junkpile, and the other for what looks like = a >> high-voltage >> automotive diode 1N3191. Can anyone tell me why an = automotive >> diode would work for this, OR whether something else = fairly >> common >> might work? I have a no-brand small-area photodiode = with a >> glass lens available. > >Would a solar cell work? > >-- >http://www.piclist.com#nomail Going offline? Don't AutoReply us! >email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body