It has long been known that the simple combination of a depletion-mode MOSFET (and before these were available, a JFET) and a resistor made a simple, serviceable current source such as that seen on ...

Measuring only 15 x 15 mm, the FX5959G701ADJ dc/dc converter claims to be not only the first complete constant-current-source module to include all necessary components in a single package, but also ...