You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Figure 35. A typical circuit using “Zero-bias” triodes showing<br />
metering circuits. The grid is grounded to r-f with a<br />
by-pass capacitor. The grid is raised 1Ω above d-c<br />
ground to allow the grid current to be measured.<br />
Some Eimac triodes are designed with a grid flange that support<br />
the tube directly on the chassis and thereby provides the lowest<br />
inductance connection possible (see fig. 36), while simultaneously<br />
eliminating the need for a socket.<br />
Figure 36. 3CX5000A7 with grid flange<br />
In grounded-grid circuits, the cathode lead inductance must be<br />
minimized to prevent loss of drive power before it reaches the<br />
grid-cathode region of the tube. The problem is similar to that seen<br />
in grid-driven circuits (discussed in Section 3.5.5). Several Eimac<br />
triodes have more than one cathode terminal (for example the<br />
3CX800A7 has 6 of the 11 pins tied to the cathode). In VHF circuits<br />
60
Change language