That design will work quite nicely for a constant current source. The only problem with that design is that it is fairly temperature sensitive.
Marshall Ode Coyote wrote: > Try this one with PNP transistors...it does work. > 1k instead of the pot gives about 1 ma > Picture isn't as nice. > > Ode > > At 11:51 AM 6/25/2004 -0400, you wrote: > >I see no way that would limit current. That is the workings of an SCR, > which is > >an on/off device. I have used an identical circuit many times (in fact I > have > >a patent on using such a configuration as a PUT) in place of a low voltage > scr > >or put. > > > >Marshall > > > >Dave Lewis wrote: > > > >> Hi all, > >> A colleague of mine has come up with this useful circuit. It limits to > >> current to just under 1ma, but if you change the value of R1, you should be > >> able to set the current to what you like (within reason!). Don't get too > >> hung up if you can't find the correct transistors, just make sure they are > >> bipolar and PNP and NPN as per the diagram. > >> > >> Dave. > >> > >> ------------------------------------------------------------------------ > >> Name: I limit.gif > >> I limit.gif Type: GIF Image (image/gif) > >> Encoding: base64 > > > > > >-- > >The Silver List is a moderated forum for discussing Colloidal Silver. > > > >Instructions for unsubscribing are posted at: http://silverlist.org > > > >To post, address your message to: silver-list@eskimo.com > >Silver List archive: http://escribe.com/health/thesilverlist/index.html > > > >Address Off-Topic messages to: silver-off-topic-l...@eskimo.com > >OT Archive: http://escribe.com/health/silverofftopiclist/index.html > > > >List maintainer: Mike Devour <mdev...@eskimo.com> > > > > > > ------------------------------------------------------------------------ > Name: CONTROL1.GIF > CONTROL1.GIF Type: GIF Image (image/gif) > Encoding: base64
