MdntTrain wrote:
On Apr 25, 12:14 pm, Michael Black <et...@ncf.ca> wrote:Grounded grid is the same arrangement with tubes. Relative low input impedance, relative high output impedance, and not much gain. Really useful to transform impedance from low to high, and often good if you need some gain but don't want to fuss with instability. And it's a non-inverting stage.I get it now, thank you also. In my tube audio tinkerings, I've never needed this configuration thus it seemed kinda strange at first.
One place you may have encountered it without realizing is in the typical dual-triode "inverter" stage used in audio amplifiers to drive a push-pull stage. In the so-caled "long-tailed pair", the input signal is applied to one triode which functions as both a buffering inverter and as a cathode follower to drive the cathode of the second triode which is a gounded-grid non-inverting stage. The differential outputs from the plates of the two triodes are used to drive the push-pull stage(s) following. The fairly large-valued common cathode resistor is the "long tail", and the degeneration it provides makes the stage very linear. -michael NadaPong: Network game demo for Apple II computers! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."