Battery to create reference below ground [More CV approaches

[petemoore]

  to create a voltage which is greater than the current [to tell the truth when comparing them, they're like apples and oranges...as far as where a voltage decimal would place in a current quantifying number].
  For purposes of diddling with the NSL-32 [or other LED] starting with too small a voltage supply.. a battery placed between supply ground and the reference for cathode, to create a supply V which is -2v from Gnd.   
  have LEd, will check it out.

[puretube]

Or lift the zero-refernce of whatever it is driving, or driving it ~ a diodedrop? (think: cathode-resistor)