The FETs of this circuit can be the BF245. The circuit is from an old documentation and can be used in the amplification of infrasonic waves, of a sonic attack, for example.
In this amplifier, the supply voltage is 35 V and the input resistance is 2k2. Equivalent...
This high speed laser diode driver was found in a 1980s documentation. Power FETs can be replaced...
This instrumentation amplifier with differential inputs was found in documentation from the 90s....