The very small
wavelength of electrons means that the obstacles used to diffract them must also be very small such as the atomic lattice. Electrons are accelerated in an electron gun to a potential of 4000 V and fall on a thin sheet of graphite. The electrons diffract from the
carbon atoms giving a circular pattern on the screen.
The diffraction pattern observed on the
screen is a series of concentric rings.
A larger accelerating voltage reduces the diameter of a given ring.