What is the difference between active and passive loading?

Question

Loading in a Material Testing sense.

Answer 1

There can be a number of definitions describing "active" and "passive" loading.

In terms of electronics: active loading would be something like coupling a signal out of a source through a resistor or capactior directly into a circuit load.  Passive coupling would be like inductive coupling a signal from its source into a load, such that the only coupling link is EMF.

Now, material testing, may be slightly different. Active loading in that sense may be applying a stress directly to a material in order to evaluate "change" in the material as a function of stress. Passive loading, may refer to indirectly applying a stress to a material through some other medium that may or may not be in direct contact with the material under test.

That's my best guess.