Compound
Scanning Electron Microscope (SEM)
Transmission Electron Microscope (TEM)
SEM use electron illumination. The image is seen in 3D. It has high magnification and high resolution. The specimen is coated in gold and the electrons bounce off to give you and exterior view of the specimen. The pictures are in black and white.
TEM is electron illuminated. This gives a 2-D view. Thin slices of specimen are obtained. The electron beams pass through this. It has high magnification and high resolution.
$100-$1500
more than $50.000
more than $50,000
visible light
electrons
electrons
air
vacuum
Dissection
Compound microscopes are light illuminated. A dissection The image microscope is seen with this light type of illuminated. microscope is The image that two appears is three dimensional. dimensional. It Description This is used for microscope is dissection to the most get a better look commonly at the larger used. You can specimen. You view individual cannot see cells, even individual cells living ones. It because it has a has high low magnification. magnification. However, it has a low resolution. Costs Source of Radiation for Image Formation
$150 - $1500 visible light
air Medium
Specimen mounting
Nature of Lenses
vacuum
glass slides
glass
none
gold
glass
glass
Thin films of collodion or other supporting material on copper grids Magnetic fields or electrostatic lenses
Focusing
mechanical mechanical
Magnification Adjustments
changing objectives
Major Means of Providing Specimen Contrast
Light Absorption
Images
usually 1 objective
light absorption
electrical
electrical electron scattering
Electrical i.e. current of the objective lens coil is changed. Electrical i.e. changing current of the projector lens coil Electron scattering