One of the most essential part of the microscope is the microscope lamp. It is the next most significant part that a microscope user needs because it is the means by which it is illuminated. Microscope lamps come in a diversity of envelope shapes (cylindrical, rounded envelope), mounting fixtures (bayonet, screw-thread or pin base) and filament configurations. The diminutive two-pin halogen lamp is extensively used in microscopes manufactured in Japan, the U.S. and Western Europe. It economically produces brilliant uniform illumination, has a small dimension and a longer life. More than a few different lamps or light sources are used in microscopes to deliver a high intensity, bright light for optimum viewing. For customary observation and photomicrography (photography through the microscope), a long life, low cost, incandescent tungsten halogen bulb is frequently used. The long-life xenon lamp, 75 to 150 watts, is another lamp often used due to its brightness, even output across the visual spectrum, and a color temperature that approximates daylight. When there is no internal light source, external ring illuminators are used. These typically use incandescent tungsten bulbs. While most modern microscopes have a built-in illumination system, the requirements of a freestanding lamp are considered in this article, on account of the greater flexibility of adjustment and alignment offered by this lamp type