controls:

acceleration voltage Va
plate voltage Vp

$E=\frac {V_{\text p}}{\text d}=$ ${0}$ $\frac {\text V}{\text m}$

schematic diagram:

Schematic layout of the experiment

Developing Equations of Motion in an Electron Deflection Tube

Real experiment about deflection of electrons in electric field of a plate capacitor
y(x) =