Investigating potential power current sources capable of handling both AC and DC currents using the LM317 current source.

In his video [Afroman] describes how the LM317 can be used to regulate current rather than voltage to provide a constant current ... While this circuit may not be as efficient as an LED driver ...

How easy is that? An LED tester can be as easy as a constant-current power supply, and in fact that’s what [Dave]’s first LED tester was, in essence. Set an LM317 circuit up to output 10mA ...