Now, I will give an overview of construction of different capacitor. For that, we will
first discuss the basic construction of paper capacitor. This is very simple. Here, one
paper is placed on a piece of aluminum foil, and then another aluminum foil is placed on
that paper. Again, one paper is placed on that aluminum foil. In this way, it will be
repeated as per requirement. The paper functions here, as dielectric medium. After this, this
assembly is rolled up and covered with a cylindrical capsule as shown. Now, the arrangement is
sealed with two metal end caps. The terminal connection, are projected or soldered on this
end cap. This is the most basic construction of paper capacitor. I forgot to tell one thing, that, each piece of aluminum foil is so placed that each alternative
foil touches either metallic end cap to form opposite electrodes of capacitor. Now, we
will come to air capacitor. Air capacitors are generally variable capacitors. There are
two sets of parallel plates. One set of plates is fixed and another set of plates is movable
When the knob connected with the capacitor is rotated, the movable set of plates rotates
and overlapping areas between fixed and movable plates vary. This causes variation in effective
cross sectional areas of the capacitor. Consequently, the capacitance varies when one rotates the
knob attached to the air capacitor. This type of capacitor is generally used to tune the
bandwidth of a radio receiver. Next, we will come to plastic capacitor. Plastic capacitors
are also in form of film capacitors which is called plastic film capacitor. In plastic
capacitor, metallic strips and plastic strips are placed alternatively. One set of alternative
metal strips are connected to contact layer of one side and other set of alternative metal
strips are connected to contact layer of other side. Terminals of capacitor are also
connected to contact layer. Whole assembly is covered with plastic cover and bottom of
the capacitor is also sealed with non-metallic insulated material. Now, we will come to ceramic
capacitor. Here, one ceramic disc is placed in between two metallic disc as show. Terminals
of capacitor are soldered with metal disc as shown. Whole assembly is dipped into a
liquid chemical of protective coating for covering the capacitor. This protective coating
becomes hard when it is dried. I have tried to give a basic idea for construction of mainly
four common types of capacitors. There are many other types of capacitors. But these
are mostly used capacitors. Anyway, thank you. Keep serving electrical for you.com