I use the method of protection that Alpha used on the 77-SX/DX
series. I select an RFC to place between the tube cathode(s) and
the zener that has very small winding; just enough to pass the normal
operating current. In addition, ala Henry, a cathode fuse is installed
in the B- line. In the few glitches I have experienced over the years,
the fuse has always gone first, protecting the tube(s), zener, and RFC.
(((73)))
Phil, K5PC
> > ** During an HV- to gnd arc,
> > no -- but during a VHF/UHF
> > parasite, an
> > 8877 is capqable of >50A-pk
> > cathode current (Ik).
> > However, 50A would
> > torpedo a 10A transistor (Q1).
>
> Doesn't your proposed opto controlled
> bias switching transistor have the same
> torpedo problem during a parasitic??
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