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A Kelvin bridge, also called a Kelvin double bridge and in some countries a Thomson bridge, is a measuring instrument used to measure unknown electrical resistors below 1 ohm. It is specifically designed to measure resistors that are constructed as four terminal resistors.
One sort of photodetector, the photoresistor, has a resistance which varies with illumination. The strain gauge, invented by Edward E. Simmons and Arthur C. Ruge in 1938, is a type of resistor that changes value with applied strain. A single resistor may be used, or a pair (half bridge), or four resistors connected in a Wheatstone bridge ...
Four-point measurement of resistance between voltage sense connections 2 and 3. Current is supplied via force connections 1 and 4. In electrical engineering, four-terminal sensing (4T sensing), 4-wire sensing, or 4-point probes method is an electrical impedance measuring technique that uses separate pairs of current-carrying and voltage-sensing electrodes to make more accurate measurements ...
The best-known bridge circuit, the Wheatstone bridge, was invented by Samuel Hunter Christie and popularized by Charles Wheatstone, and is used for measuring resistance. It is constructed from four resistors, two of known values R 1 and R 3 (see diagram), one whose resistance is to be determined R x, and one which is variable and calibrated R 2.
Tammann temperature was pioneered by German astronomer, solid-state chemistry, and physics professor Gustav Tammann in the first half of the 20th century. [1]: 152 He had considered a lattice motion very important for the reactivity of matter and quantified his theory by calculating a ratio of the given material temperatures at solid-liquid phases at absolute temperatures.
A metal object C (Faraday used a brass ball suspended by a nonconductive silk thread, [1] but modern experiments often use a small metal ball or disk mounted on an insulating handle [4]) is charged with electricity using an electrostatic machine and lowered into the container A without touching it. As it is lowered the charge detector's reading ...
One of the fragments was made of bloomery iron rather than meteoritic iron. [37] [38] The earliest iron artifacts made from bloomeries in China date to end of the 9th century BC. [39] Cast iron was used in ancient China for warfare, agriculture and architecture. [9] Around 500 BC, metalworkers in the southern state of Wu achieved a temperature ...
Slider of Kelvin's ampere balance. Approximate readings may be obtained by reading the position of the weight on the scale, or a more accurate reading may be obtained as follows: The upper edge of the shelf on which the weights slide is graduated into equal divisions, and the weight is provided with a sharp tongue of metal in order that its position on the shelf may be accurately determined.