Some augmented cathode follower circuits

Some direct-coupled augmented cathode-follower circuits are described suitable for power-tube grid drivers, coaxial cable drivers, high-input impedance isolation stages, active electronic filters and frequency selective circuits. One of the circuits, using only double triodes, has an input-output voltage transfer ratio of 0.995 or greater with no phase reversal, can supply up to 100 ma of positive current has a freqency response essentially flat from zero up into the megacycle-second range can have an input capacitance approaching or equal to zero exhibits an input resistance greater than 10¹¹ohms for input swings of ±100 volts or more using ordinary unselected receiving tubes has an output resistance of 3 ohms, will handle a dynamic range of 630 volts peak-to-peak, and shows less than one part in a million total harmonic distortion at 20-volts runs output and only two parts in 10⁵distortion at 100 volts rms output.