There are two categories of microscopes based on the principle on which magnification is achieved, Light microscopes and Electron microscopes (EM). In Light or optical microscopes, magnification is obtained by a system of optical lenses using light waves. Electron microscope (EM) uses beams of electrons to produce images. In overall design, EM is similar to light microscopes with some differences (Refer: Electron Microscope  vs Light Microscope)
Electron microscope was designed by Knoll and Ruska of Germany in 1932. There are two types of electron microscopes: TEM (Transmission Electron Microscope) and SEM (Scanning Electron Microscope) 
 Scanning Electron Microscope (SEM) vs Transmission Electron Microscope (TEM)
SEM vs TEM

Scanning Electron Microscope (SEM)
Transmission Electron Microscope (TEM)
Used to produce excellent images of the surfaces of cells and small organisms. Excellent for studying surface morphology of the organisms, cells or any suitable material under study
Used to study the ultra structure of the cell and its components. It can see objects as small as a protein molecule or even at nano level. Provides details about internal composition of cells or any suitable material under study
Electron beam scans over the surface of the sample
Electron beam pass through the sample
Based on scattered electrons or produces images by detecting secondary electrons which are emitted from the surface due to excitation by the primary electron beam
Based on transmitted electrons or produces images by detecting primary electrons transmitted from the sample
Comparatively low resolution than TEM; Resolution: 2nm(Average), 0.2nm (Special)
High Resolution; Resolution: 10 nm (Average), 0.5nm (Special)
Depth of field: High
Depth of field: Moderate
Magnifying power: 100,000X
Magnifying power: 5,000,000X
Specimen contrast:  by electron adsorption
By electron scattering
Produces three-dimensional black and white images
Produces two-dimensional black and white images
Preparation technique: easy
Skilled, very thin sample is required
Preparation thickness: variable
Very thin
Specimen mounting: Aluminium stubs
Thin films on copper grids
Field of view:  Large
Limited


Similarities between SEM and TEM
·         Type of object : Non living
·         Source of radiation: Electron
·         Medium: High vacuum
·         Nature of lenses: one electrostsastic and a few electromagnetic lenses
·         Magnification Adjustment: Current in the projector lens coil
·         Focusing: Current in the objective lens coil
Image credit:1) http://remf.dartmouth.edu/imagesindex.html  2) https://www.paldat.org/pub/Tilia_platyphyllos/109978

18 Comments

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  1. tatenda biotechnologist13 October 2016 at 04:37

    nice piece of information

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  2. Based on the table, it looks like the SEM has higher resolution than the TEM. Otherwise, this is an awesome comparison!

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  3. Really helpful table - concise and informative, thanks!!

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  4. Good information but resolution of Sem is 10 nm normally and not of TEM .TEM has higher resolution so it is normally 0.2nm.

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  5. I liked the most this one.Very clear and neat.well done u are amazing

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  6. Resolution figures don't make sense?! How is 2nm lower resolution than 10nm? Other than being numerically smaller, I would have thought it is greater resolution because it has a greater ability to *resolve* details.

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  7. Useful piece of information. Thank you.

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  8. wow - pete heitmeyer

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  9. thank you very much. This is short, neat, and easy to understand

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  10. thank you very much. This is short, neat, and easy to understand

    ReplyDelete
  11. Thank you, the write was very helpful

    ReplyDelete

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