# Electronic – Current Notation in BJT

bjtmath-notation

We are currently studying BJTs in electronics I and I am a bit confused on the notation of the current, specifically the collector current here. Throughout this chapter they will swap $$\I\$$ and $$\i\$$ to seemingly refer to the exact same thing. The book itself doesn't explain it either. There seems to be no consistency. Why wouldn't it just be $$\I_{C1}\$$ and $$\I_{C2}\$$? I understand that usually lower case refers to instantaneous voltage or current, but when solving this example, for instance, $$\I_c\$$ and $$\i_c\$$ are simply different examples used to solve the $$\i_c = I_{s}e^{V_{BE}/V_T}\$$ equation to give the $$\V_{BE}\$$ needed for the design choice.
I cannot find any other info on this so I figured this was a good chance to ask here.