Figure 91.
How the Voltage and Magnetic Field
Affect Electron Movement.
15. Now change the cathode voltage.
a. Now, let's use the same magnet, but change the cathode voltage. You
can see in Part B of Figure 91 that as we lower the cathode voltage, the
electrons take a more curved route to the anode. In fact, if the cathode
voltage is too low, the electrons never reach the anode.
b. From this you can see that the cathode voltage and magnetic field
strength work hand in hand.
Increasing the magnetic force has the same
effect as lowering the cathode voltage.
And by keeping one steady and
varying the other we can change the path of the electrons.
c. In practice there is only one correct combination of magnetic field
strength and cathode voltage that gives the desired output from the
magnetron oscillator.
The correct combination is one that causes the
electrons to reach the anode only after they pass by some of the resonant
cavities in the magnetron.
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