Post by thread:[EE]:: MEasuring nanoamperes

Better than average EDN technical article with some good insights into measuring nanoamperes and below. http://www.edn.com/index.asp?layout=article&articleid=CA6434367 Mentions a Paul Grohe and Bob Pease lashup that resolved 1 Femtoamp. Suspended on rubber bands. Looks like some of the things I have built over the years. No doubt works a lot better :-). http://www.edn.com/contents/images/6434367f4.pdf Russell

Very interesting. I am not a physicist, but the author makes reference to radium-painted wristwatches producing "cosmic radiation effects" - I think the more likely (possible) cause is that the radium produces radon, and the radon is thus a significant source of alpha-induced ions in the air. - Martin Apptech wrote: {Quote hidden}> Better than average EDN technical article with some good > insights into measuring nanoamperes and below. > > www.edn.com/index.asp?layout=article&articleid=CA6434367 > > Mentions a Paul Grohe and Bob Pease lashup that resolved 1 > Femtoamp. > > Suspended on rubber bands. Looks like some of the things I > have built over the years. No doubt works a lot better :-). > > www.edn.com/contents/images/6434367f4.pdf > > > Russell >

>Very interesting. I am not a physicist, but the author makes reference >to radium-painted wristwatches producing "cosmic radiation effects" - I >think the more likely (possible) cause is that the radium produces >radon, and the radon is thus a significant source of alpha-induced ions >in the air. My guess is that he's referring to the high energy gamma rays produced by the radium, the alphas would not be able to penetrate the coax. -- --- Chris Smolinski Black Cat Systems http://www.blackcatsystems.com

Thanks Russell, I've just discovered our corporate IT people have now blocked ETN magazine due to "inappropriate content" !!!! (just as well I have a workaround) RP 2008/5/7 Chris Smolinski <spam_OUTcsmolinskiTakeThisOuTblackcatsystems.com>: {Quote hidden}> >Very interesting. I am not a physicist, but the author makes reference > >to radium-painted wristwatches producing "cosmic radiation effects" - I > >think the more likely (possible) cause is that the radium produces > >radon, and the radon is thus a significant source of alpha-induced ions > >in the air. > > My guess is that he's referring to the high energy gamma rays > produced by the radium, the alphas would not be able to penetrate the > coax. > > -- > > --- > Chris Smolinski > Black Cat Systems > http://www.blackcatsystems.com > > > --