Parts of the compound light microscope and their functions

Oculars (eyepieces)

used for magnification or to enlarge the specimen 10 times (10x)

Objectives

used to magnify or enlarge the specimen

Scanning power objective lens

(4x)

Low power objective lens

(10x)

High-dry power objective lens

(40x)

Oil immersion objective lens

(100x)

Revolving Nosepiece

rotates the objectives and allows one of them to be positioned over the slide

Arm

supports the viewing components of the microscope and connects the lower base to the upper head of the microscope, which supports the ocular lens and revolving nosepiece

Base

supports the microscope and holds the illuminator components

Illuminator (substage light)

the light source and is fitted into the microscope’s base providing the light necessary to view the specimen

Stage

supports the slide containing the specimen

Stage clips

clamps to hold the slide in place

Aperture

the hole in the center of the stage that lets light pass from the illuminator through the object being examined

Slide position adjustment knobs (mechanical stage controls)

used to move the slide on the stage to center the specimen in the field of view over the aperture

Coarse (focus) adjustment knobs

the larger diameter knobs located on each side of the arm and they are used to locate the specimen by raising or lowering the stage

Fine (focus) adjustment knobs

the smaller diameter knobs found on each side of the arm and they are used to sharpen focus after the object has been brought into view using the coarse focus knob

Condenser

located beneath the stage and it concentrates the light from the illuminator

Iris Diaphragm

located on the condenser. It is a lever that regulates the amount of light that passes through the specimen to the objective