Why does LTSpice simulation give me negative value on NPN emitter current?
This is what I found in the Electronic Devices book by Stephen Fleeman.  


  During the development of the V-I curves (and on manufacturers' data
  sheets), it is customary to apply the transistor convention.  The
  transistor convention has been defined in Fig. 4-10(a). 
  
  Currents that flow into the transistor are called positive.
  Conversely, currents that flow out of the transistor are called
  negative. If the actual conventional current directions agree with the
  transistor convention, they are called positive. If not, they are
  called negative.