The 2SJ125C from Isahaya Electronics is a Junction Field Effect Transistor (JFET) with Drain Saturation Current 1.0 to 3.0 mA, Gate Source Voltage 50 V, Forward Transfer Admittance 1.5 to 4.0 mS, Continous Drain Current -1.0 to -12 mA, Drain Source Resistance 220 Ohm. Tags: Surface Mount. More details for 2SJ125C can be seen below.