[R-390] Tube testers

[Gord Hayward]

> The reality of a tube tester is actually worse than it looks at first. 
> Often they are set up to do a measurement that is affected

> by the DC current through the tube. A tube with high DC leakage will 
> pass the test on a tester set up this way ....


I agree in part.  The tube tester didn't catch the small 
filament-cathode leakage that plagued my noise limiter.  That being
said, I get a lot of tubes at flea markets and the tester lets me cull 
the duds.  Emission testers get some but then I acquired
a transconductance tester and the end results got a lot better. 
 Everything has its place.

Cheers es 73 de Gord, VE3EOS

-- 

Gordon L. Hayward, Ph.D., P.Eng.,
Associate Professor, Biological Engineering,
School of Engineering, University of Guelph,
Guelph, Ontaro, N1G 2W1.