Transmission Electron Microscopy (TEM) employs a sophisticated design comprising several key components to achieve its remarkable imaging capabilities. At the heart of the TEM system is the electron source, typically a tungsten filament or field emission gun, which emits a high-energy beam of electrons. These electrons are accelerated through a series of electromagnetic lenses, including condenser lenses, which focus the beam onto the specimen.

The specimen itself is prepared as an ultra-thin section, often less than 100 nanometers thick, to enable electron transmission. This thin section is typically mounted on a grid made of materials such as copper or gold, which support the specimen during imaging.

As the electron beam passes through the specimen, it interacts with the atoms and electrons within, undergoing processes such as transmission, scattering, and diffraction. These interactions produce various signals that carry information about the specimen's internal structure, including its morphology, crystallography, and elemental composition.

On the other side of the specimen, a series of detectors capture the transmitted electrons and convert them into an image. Common detectors include scintillation screens coupled with photographic film or digital cameras, as well as more advanced detectors such as CCD cameras or direct electron detectors.