"To fight the bug, we must understand the bug."
--SKY MARSHALL TEHAT MERU
The J113 datasheet (Fairchild)
tells you the following important information,
1. The (absolute) maximum gate-source / gate-drain voltage is 35 V.
2. The gate-source cut-off voltage (V_gs0) varies between -0.5 and -3 V.
3. The minimum zero-gate voltage drain current (I_dss) is 2 mA.
4. (from Fig. 11) the transconductance for I_ds 1-10 mA is about 10 mS largely independent of V_gs0.
5. (from Fig. 14) the voltage noise rises at low frequency and decreases with drain current, but is about 2-4 nV/sqrtHz over most of the audio bandwidth.
I bought 200 J113 off eBay, but my measurements were set back after I realized my test rig was oscillating. Fixed that, and can now say a few things in addition to the datasheet.
The first is that the transfer curve (measured at RT, V_ds 10 V) does...