[Jasper’s] electronic load can not only act as a constant current load, but also as a constant power and constant resistive load as well.

In Constant Resistance Mode, set as resistance conductance, the unit will maintain a constant resistive load by varying the current.

By pairing a visible-light LED (VLED) with a depletion-mode MOSFET, you can create an efficient, controllable current-source driver.