3.6M north10.pdf - Dean-O's Toy Box

172 High-Power Microwave-Tube Transmitters
)3
O*
00
o
0-
Shield grtd
Conlrd grkl
Anode -J
Figure 10-15.
Section view through active region of type 6544 shield-grid
triode.
view in Fig. 10-15, are intended to contribute to a high-p triode (K = 90), which
carries the implication that it has high grid-current interception, but without the
high grid current. The cathode is of cylindrical shape, but its coated active
emitting surfaces by no means cover the entire available surface. In fact, as
shown, the individual emitting surfaces are groovelike concavities spaced around
the periphery. Control-grid rods, held in place by ringlike headers at each end,
run the length of the emitting grooves, but they are staggered in spacing with
respect to grooves so that they are in between them and not in the line of fire of
electrons leaving the cathode on the way to the anode. The shield grid is another
F’ a > r 3 J
CaIhcd Control grid Shmld grid Anode
Figure 10-16. View of concentric subassemblies that makeup the type 6544 shield-grid triode.