Computing Mouse. How Stuff Works

Computer Mouse ( Computing Mouse) is the input device of the computer which is a pointing device that detects the two dimensional motion relative to its supporting surface. The mouse has two or three buttons, to control the desktop screen and to provide various commands to the PC. The mouse sometime has a wheel to perform system dependent operations. The motion of the mouse is translated into the motion of the pointer on the display which controls the Graphical User Interface (GUI). Old type mouse has a ball to move on the surface but modern optical mouse uses reflected light to activate the circuitry inside. The Optical mouse has one or more Red LED and a Photodiode detector to accept the reflected light from the LED. The Photodiode detects the mouse movement relative to the underlying surface such as mouse pad or table top. In some mouse, laser is used instead of LED. The driver communicate the mouse movements in standard units called “Mickeys”

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Stethoscope. How Stuff Works

Stethoscope is a medical diagnostic tool for Auscultation which is the listening of internal sounds of the body. Auscultation is used to examine the heart sounds, breath sounds, bowel sounds etc. Auscultation requires skill,  clinical experience and a good quality stethoscope. An experienced physician can distinguish normal Lub and Dub sounds of the heart as well as heart murmurs and gallops. In combination with the sphygmomanometer, the Stethoscope is used to measure the blood pressure. The Stethoscope was invented by Rene Laennec of France in 1816. The two-sided stethoscope was invented by Rappaport and Sprague in the early 20th century.

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