17-04-2012, 04:53 PM
Mark - F.E.T.s versus bi-polar transistors. One advantage that a F.E.T. does have over bi-polars in an application like this is that the input impedance of a F.E.T. is much higher that what can (usually) be obtained with a bi-polar, leading to a higher loaded Q of the input tuned cct. - a desirable feature in such an elementary receiver.
As for variations in gm, in the past I've always been fortunate enough to have a generous quantity of '3819s to play with - and thus measure and select the one with the highest figure (if the gm is critical to the application).
Al.
As for variations in gm, in the past I've always been fortunate enough to have a generous quantity of '3819s to play with - and thus measure and select the one with the highest figure (if the gm is critical to the application).
Al.
