I've gotta be somewhere soon, so can't respond fully (I'm a slow composer) but just wanted to at least make the point that it was the LD's effective resistance at that voltage/current. Its "resistance" is kind of slippery.
:-?
...and basically, the reason for not using an ammeter is insertion loss - you'll find that your meter introduces resistance to the circuit, varying depending on what range it is on. That's because your meter is measuring voltage across an internal resistor!
:-?
...and basically, the reason for not using an ammeter is insertion loss - you'll find that your meter introduces resistance to the circuit, varying depending on what range it is on. That's because your meter is measuring voltage across an internal resistor!