(13-11-2016, 04:01 PM)Sparks Wrote: I have just been looking in my Radio Valve and Transistor Sata Ninth Edition. and find them puzzling.
Taking two valves that I am familiar with, the pentode EF39 and the triode 6C4, this details under gm in mA/V show:
EF39 = 2.2 mA/V (All very clear)
6C4 = 7,700 mA/V (Not very clear at all)
What is the explanation for this?
Most of the triodes are shown up in the thousands. All I can think of it that the commas should be decimal points, and the gm of the 6C4 is, in fact 7.7mA/V
Output valves do not have gm listed at all!
Bob
You need the valve data sheets, here's one for a 6C4, mutual conductance is clearly stated for two sets of operating conditions:
http://www.r-type.org/pdfs/6c4-1.pdf
Valve data sheets for output valves should also give mutual conductance figures, here's an example for the EL84:
http://www.r-type.org/pdfs/el84.pdf
EDIT: Whoops...post crossed with Alan's...He's right, be careful not to confuse with ra or micromhos
Lawrence.
