Source follower: A misunderstood humble circuit

The paper demonstrates that the source follower is the core of such seemingly disparate circuits as the wideband amplifier, crystal oscillator and emitter-coupled multivibrator. It is shown that the input impedance of the follower loaded by a capacitor has a negative real part. This part compensates partially or completely the resistive component of the signal source impedance. The compensation develops a strong overshoot in the step-signal transmission; in case of inductive component in the source impedance the circuit may operate as well as oscillator. The oscillators can be also obtained coupling two source followers; this may result in new oscillator circuits.