Found in an American documentation from the 90s, this circuit has a configuration that has been extensively explored in other articles on this site. The FET can be the MPF102 or equivalent.
With this configuration we have a voltage follower, amplifier with unit gain, in which the output...
This circuit is from the Linear Circuits Application of Texas Instruments, using an operational amplifier...
This amplifier, suggested by National Semiconductor (Now Texas Instruments), has high input...