In microelectronics, a dual in-line package, is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. The dual-inline format was invented by Don Forbes, Rex Rice and Bryant Rogers at Fairchild R&D in 1964, when the restricted number of leads available on circular transistor-style packages became a limitation in the use of integrated circuits. Increasingly complex circuits required more signal and power supply leads ; eventually microprocessors and similar complex devices required more leads than could be put on a DIP package, leading to development of higher-density chip carriers. Furthermore, square and rectangular packages made it easier to route printed-circuit traces beneath the packages.
A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for accurate measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. Micrometers are usually, but not always, in the form of calipers. The spindle is a very accurately machined screw and the object to be measured is placed between the spindle and the anvil. The spindle is moved by turning the ratchet knob or thimble until the object to be measured is lightly touched by both the spindle and the anvil.
A ruler, sometimes called a rule or line gauge, is a device used in geometry and technical drawing, as well as the engineering and construction industries, to measure distances or draw straight lines.
A vernier scale, named after Pierre Vernier, is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation, thereby increasing resolution and reducing measurement uncertainty by using vernier acuity to reduce human estimation error.It is use to calculate internal and external diameter of hollow cylinders.
An alidade or a turning board is a device that allows one to sight a distant object and use the line of sight to perform a task. This task can be, for example, to triangulate a scale map on site using a plane table drawing of intersecting lines in the direction of the object from two or more points or to measure the angle and horizontal distance to the object from some reference point Polar measurement. Angles measured can be horizontal, vertical or in any chosen plane.
A tape measure or measuring tape is a flexible ruler used to measure size or distance.
A combination square is a multi-purpose measuring and marking tool used in metalworking, woodworking, and stonemasonry. It is composed of a rule and one or more interchangeable heads that can be attached to the rule.
A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles.
A meterstick or yardstick is either a straightedge or foldable ruler used to measure length, and is especially common in the construction industry. They are often made of wood or plastic, and often have metal or plastic joints so that they can be folded together. Normal length of a meterstick made for the international market is either one or two meters, while a yardstick made for the U.S. market is typically one yard long.
A caliper is a device used to measure the dimensions of an object.
In various contexts of science, technology, and manufacturing, an indicator is any of various instruments used to accurately measure small distances and angles, and amplify them to make them more obvious. The name comes from the concept of indicating to the user that which their naked eye cannot discern; such as the presence, or exact quantity, of some small distance.
A marking gauge, also known as a scratch gauge, is used in woodworking and metalworking to mark out lines for cutting or other operations. The purpose of the gauge is to scribe a line parallel to a reference edge or surface. It is used in joinery and sheetmetal operations.
A spherometer is an instrument used for the precise measurement of the radius of curvature of a sphere or a curved surface. Originally, these instruments were primarily used by opticians to measure the curvature of the surface of a lens.
Stadiametric rangefinding, or the stadia method, is a technique of measuring distances with a telescopic instrument. The term stadia comes from a Greek unit of length Stadion which was the typical length of a sports stadium of the time. Stadiametric rangefinding is used for surveying and in the telescopic sights of firearms, artillery pieces, or tank guns, as well as some binoculars and other optics. It is still widely used in long-range military sniping, but in many professional applications it is being replaced with microwave, infrared, or laser rangefinding methods. Although much easier to use, electronic rangefinders can give away the shooter's position to a well-equipped adversary, and the need for accurate range estimation existed for much longer than electronic rangefinders small and rugged enough to be suitable for military use.
A thousandth of an inch is a derived unit of length in a system of units using inches. Equal to 1⁄1000 of an inch, a thousandth is commonly called a thou or particularly in North America a mil.
A scale ruler is a tool for measuring lengths and transferring measurements at a fixed ratio of length; two common examples are an architect's scale and engineer's scale. In scientific and engineering terminology, a device to measure linear distance and create proportional linear measurements is called a scale. A device for drawing straight lines is a straight edge or ruler. In common usage, both are referred to as a ruler.
A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points or heights of points above a vertical datum. It cannot be used without a leveling instrument.
A dividing engine is a device employed to mark graduations on measuring instruments to allow for reading smaller measurements than can be allowed by directly engraving them. The well-known vernier scale and micrometer screw-gauge are classic examples that make use of such graduations.
Transversals are a geometric construction on a scientific instrument to allow a graduation to be read to a finer degree of accuracy. Transversals have been replaced in modern times by vernier scales. This method is based on the Intercept theorem.
A diameter tape (D-tape) is a measuring tape used to estimate the diameter of a cylinder object, typically the stem of a tree or pipe. A diameter tape has either metric or imperial measurements reduced by the value of π. This means the tape measures the diameter of the object. It is assumed that the cylinder object is a perfect circle. The diameter tape provides an approximation of diameter; most commonly used in dendrometry.
