This circuit can supply currents adjusted by R1 in a range of values that depend on the transistors used. The circuit is from an Electronics Now magazine from October 1998. For the types indicated a maximum of 20 mA.

This circuit can supply currents adjusted by R1 in a range of values that depend on the transistors used. The circuit is from an Electronics Now magazine from October 1998. For the types indicated a maximum of 20 mA.