[Amps] Hi Mu correction

[Bill Fuqua]

Lower mu tubes have wider spacing between the grid wires allowing more 
electrons to slip by each second for the same bias voltage. It also reduces 
the effective control the grid voltage has over the plate current, thus 
lower mu. You can easily see this difference in grid wire spacing by 
comparing a 250TH with a 250TL. Or a 811 with a 812.

73
Bill wa4lav


At 11:55 PM 7/18/2006 -0400, Tony King - W4ZT wrote:
>Tom W8JI wrote:
> > I do think I made an error in the post about mu, but I
> > deleted my post.
> >
> > Higher mu in a given tube means less bias is needed to
> > maintain the same plate current. Lower mu means more bias is
> > needed to cut off the tube to the same current. The rest was
> > OK.
> >
> > 73 Tom
>
>I'm still a little confused here.  I thought that a higher mu tube
>(higher gain) would require more bias to hold it to a specific current
>(idle?) and that a lower mu tube (lower gain) would require less bias to
>hold a specific current.  Can you help me understand where I am missing
>this?
>
>Thanks and 73,
>Tony W4ZT
>
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