The document describes the parts and operation of a compound microscope. It discusses the mechanical and optical parts of the microscope. The mechanical parts include the base, pillar, arm, stage, clips, and adjustment knobs. The optical parts are the eyepiece, objective lenses, and mirror. The compound microscope uses two lens systems - an objective lens and an eyepiece - to magnify the image under examination. By using different combinations of objective lenses and eyepieces, compound microscopes can achieve magnifications ranging from 40x to 1000x.

1. Mr.Lovepreet Singh Grewal
( Lecturer in SBS college of Pharmacy )
1
AIM : Study of compound microscope
INTRODUCTION :A compound microscope is a type of microscope that uses two sets of lenses to
magnify the image under the microscope. it has an objective lens that has a resolution of 4x,10x, 40x,
100x, and an eyepiece of resolution of 10x. the usage of both lenses, compounds or magnifies the
image of the object below the objective lens to achieve a resolution of 40x, 100x, 400x, 1000x.
Parts of the compound microscope may be grouped into two major categories
 Mechanical parts
 Optical parts.
(a) Mechanical Parts:
These include base or foot, pillar, arm, inclination joint, stage, clips, diaphragm, body tube, nose piece,
coarse adjustment knob and fine adjustment knob.
(b) Optical Parts:
These include eye piece lens, objective lenses and mirror.
All these parts are briefly described below:
1. Foot or Base: It is the basal, horse shoe-shaped structure. It provides support to all the remaining
parts of the microscope.
2. Pillar: A small, strong vertical projection
developing from the foot or base is called pillar.
3. Arm: It is a curved and strong structure used
for handling the entire instrument.
4. Inclination Joint: A joint at which the arm is
attached to the pillar of the microscope is called
inclination joint. It is used for tilting the
microscope.
5. Stage: It is a flat rectangular plate attached to
the lower end of the arm. Slide or object is placed
on the stage and studied. A hole is present in the
centre of the stage. Light rays pass through this hole.

2. Mr.Lovepreet Singh Grewal
( Lecturer in SBS college of Pharmacy )
2
6. Clips:Two clips are attached on the upper part of the stage. These are used for holding the slide in
position.
7. Diaphragm: It is attached beneath the stage. It regulates the intensity or amount of light entering
into the microscope. It may be of two types viz., iris diaphragm and disc diaphragm.
8. Condenser: It is a lens situated beneath the stage. It controls the size of the light beam. It gathers
light from the mirror (Fig. 279) and directs it to objective lens. Condenser may be lowered or raised by
a knob present on one side beneath the stage.
9. Body Tube: It is the tubular, hollow part attached to the upper part of the arm of microscope. It can
be moved up and down with the help of adjustment knobs.
10. Nose Piece: It is a circular and revolving metalic part attached to the lower end of the body tube. It
has three holes in which objective lenses can be fitted.
11. Coarse Adjustment Knob: It is a large-sized knob used to move the body tube up and down for
bringing the object into focus.
12. Fine Adjustment Knob: It is a small-sized knob. It is used for fine and sharp focussing of the object.
Exact focussing is done by this knob.
Optical parts
1. Eyepiece or Ocular: It is a lens fitted at the top of the body tube. It is always marked with a number
(5X, 10X, 15X) on its rim. This number shows its magnification power. Magnified image of the object is
seen with the eyepiece.
2. Objective Lenses: Three objective lenses are attached to the revolving nose piece at the bottom of
the body tube. These are low power objective (10X), high power objective (45X) and oil immersion
objective (100X).
3. Mirror:: It is either attached to the lower end of the arm or to the pillar. It contains a plane mirror on
one side and a concave mirror on the other side. Mirror is used to reflect light rays into the
microscope.