controls:
acceleration voltage Vaplate voltage Vp
$E=\frac {V_{\text p}}{\text d}=$ ${0}$ $\frac {\text V}{\text m}$
schematic diagram:
Experiments with an Electron Defelection Tube
$E=\frac {V_{\text p}}{\text d}=$ ${0}$ $\frac {\text V}{\text m}$