In Reply to: Simple Constant Current Source posted by Mike Gray on 12/15/01 at 1:03 AM:
I just e-mailed to you, the simplest current source ciruit that I know of so far. It uses two transistors and two resistors, though, not one.
Transistors are available to take the voltage you require and although I drew the circuit as a positive current source using PNP devices, it can be made for negative currents if NPN devices are used instead.
John Dunn - President