The control grid or plate electrode is sometimes connected to a
cap on the top of an electron tube. The reason for this practice is
allow visual examination of the electrode.
allow that particular electrode to dissipate its heat.
provide an electrode that will collect the spurious electrons
rising to the top of the tube.
provide physical separation of the control grid and plate
electrodes in order to minimize grid-to-plate capacitance.
Figure 4-1 shows a tetrode circuit and the plate characteristic
Exercises 4 through 8 are based on this situation.
Note the four points:
A, B, C and D, in part A of figure 4-1.
The input of the tube in this circuit is between points
A and C.
B and D.
B and C.
C and D.
What is the value of the screen grid voltage, Ec2?