∞ generated and posted on 2016.01.14 ∞
The device that provides the direct illumination of a specimen in a compound microscope, typically found below the specimen and shining up through it.
The condenser, however, is not the illuminator, which instead is found, in terms of the path of light, upstream from the condenser.
Contrast equivalently with what can be described simply as Light source from which the microscope's light originates. From the light source or illuminator the light then travels into the condenser, or more specifically for most light microscopes, an Abbe condenser. The condenser concentrates the light on the specimen.
In modern compound light microscopes the light source is a light bulb. The pathway of light is: light source → condenser → iris diaphragm → stage → object/specimen → objective lens → ocular lens → eye or camera.
Figure legend: The condenser here is an Abbe condenser, as labeled. It is found directly above the light source, which shines directly into it. It is also found directly beneath the mechanical stage and contains the iris diaphragm.
The condenser typically will have a blue filter associated with it and a control for what is known as the iris diaphragm. The blue filter limits light to the shorter wavelengths, which increases resolution. The height of the condenser typically will also be controllable and usually you will want to keep or at least start with the condenser at its highest point.