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.
<<attachment: I limit.gif>>
