View 2sk1842 datasheet:

Silicon Junction FETs (Small Signal) 2SK1842 2SK1842 Silicon N-Channel Junction Unit : mm For impedance conversion in low frequency +0.2 2.8 –0.3 For infrared sensor +0.25 0.65± 0.15 1.5 –0.05 0.65± 0.15 Features 1 Low gate-source leakage current, IGSS Small capacitance of Ciss, Coss, Crss 3 Downsizing of sets by mini-type package and automatic insertion by 2 taping/magazine packing are available. Absolute Maximum Ratings (Tc = 25?C) Parameter Symbol Rating Unit 0.1 to 0.3 Gate-Drain voltage VGDO –40 V 0.4± 0.2 Gate-Source voltage VGSO – 40 V Drain current ID ±1 mA 1 : Source JEDEC : TO-236 Gate current IG 10 mA 2 : Drain EIAJ : SC-59 Allowable power dissipation PD 150 mW 3 : Gate Mini Type Package (3-pin) Junction temperature Tj 150 ?C Storage temperature