In a bipolar junction transistor, the emitter efficiency is (p-n-p transistor):
1
\(\rm \frac{Current \ of \ injected \ carriers \ at \ J_E}{total \ collector \ current}\)
2
\(\rm \frac{Current \ of \ injected \ carriers \ at \ J_E}{total \ emitter \ current}\)
3
\(\rm \frac{Current \ of \ injected \ carriers \ at \ J_C}{total \ collector \ current}\)
4
\(\rm \frac{Current \ of \ injected \ carriers \ at \ J_C}{total \ emitter \ current}\)