On Mon, 27 Dec 2004 03:05:57 +0100, J M Noeding
wrote:

Wonder if somebody else has experience with grounded-collector
amplifiers for amateur radio applications? See the notes on
http://home.online.no/~la8ak/c23.htm


While the collector is grounded for RF the circuit is NOT an emitter
follower. The drive is impressed via a link to the E-B of the
transistor and taken off the emitter not the base. A two port
analysis makes the characteristic behavour similar to
common emitter. The low gain was devices of the time rather
than the circuit itself.

I've seen this used in older Aircraft comm radios, at least two
different older solid state CB (ca-1969) and varios other places.

It's weakness is rather high rf feedthrough making CW and AM
system require keying the previous stage (driver) or there will be
poor keying and/or modulation. Also reflected RF (load mismach)
was reflected back to the driver resulting in poor operation under
less than optimum loading.

The upside was it made it easier to cope with the fact that the
collector was a high capacitance to a heatsink for RF.

Using modern devices and circuit techniques makes this a less
than desireable design.

Allison
Kb1gmx