If we put a battery in the grid circuit we can let EC represent the number of volts applied to the grid-filament or C-circuit.
Then we shift the slider in the grid circuit so as to give the grid a small potential.
The batteries and slide wire resistance which are connected in the grid circuit are already familiar to you.
The next step is to shift the slider in the grid circuit until we have again the original value of current in the plate circuit.
It means that two volts in the grid circuit have the same effect on the plate current as ten volts in the plate circuit.
Next we read the voltage impressed on the grid by reading the voltmeter in the grid circuit.
Connect some small dry cells in series for use in the grid circuit.
If you can, buy one which will work between the plate circuit of one vacuum tube and the grid circuit of another similar tube.
The oscillations are varied by means of the telegraph key which is placed in the grid circuit as shown in Fig. 76.
A small effect in the grid circuit produces a large effect in the plate circuit.
