Electronics

-

Electronics->> Electronic Components->> INTEGRATED CIRCUITS, RESISTORS AND CAPACITORS

Integrated Circuits

Most integrated circuits are small pieces, or “chips,” of silicon, perhaps 2 to 4 sq mm (0.08 to 0.15 sq in) long, in which transistors are fabricated. Photolithography enables the designer to create tens of thousands of transistors on a single chip by proper placement of the many n-type and p-type regions. These are interconnected with very small conducting paths during fabrication to produce complex special-purpose circuits. Such integrated circuits are called monolithic because they are fabricated on a single crystal of silicon. Chips require much less space and power and are cheaper to manufacture than an equivalent circuit built by employing individual transistors.

Resistors

If a battery is connected across a conducting material, a certain amount of current will flow through the material (see Resistance). This current is dependent on the voltage of the battery, on the dimensions of the sample, and on the conductivity of the material itself. Resistors with known resistance are used for current control in electronic circuits. The resistors are made from carbon mixtures, metal films, or resistance wire and have two connecting wires attached. Variable resistors, with an adjustable sliding contact arm, are often used to control volume on radios and television sets.

Capacitors

Capacitors consist of two metal plates that are separated by an insulating material (see Capacitor). If a battery is connected to both plates, an electric charge will flow for a short time and accumulate on each plate. If the battery is disconnected, the capacitor retains the charge and the voltage associated with it. Rapidly changing voltages, such as caused by an audio or radio signal, produce larger current flows to and from the plates; the capacitor then functions as a conductor for the changing current. This effect can be used, for example, to separate an audio or radio signal from a direct current in order to connect the output of one amplifier stage to the input of the next amplifier stage.

Comments

Post a Comment

Popular posts from this blog

Hanaoka Seishu

-
Image
A stamp depicting the image of Hanaoka Seishu. Hanaoka Seishu (1760-1835), Japanese physician and pioneer of anesthetic surgery. Hanaoka studied traditional Sino-Japanese medicine, as well as what was then known about Western surgery in Japan. For over two decades he experimented with various drugs. Ultimately he created mafutsusan, an anesthetic compound made from six traditional plant-based drugs, including the alkaloids aconite (from the monkshood plant) and datura (from jimsonweed ). In 1805, using mafutsusan as an anesthetic, Hanaoka removed a tumor during breast cancer surgery. This was the world's first recorded successful surgical operation with anesthesia. Later, Hanaoka used the drug for other surgical operations, developing techniques for bladder stone removal and for amputation. Hanaoka attracted many students, and his surgical techniques became known as the Hanaoka method.
Read more

Brahe, Tycho

-
Image
Brahe, Tycho (1546-1601), Danish astronomer, who made precise, comprehensive astronomical measurements of the solar system and more than 700 stars . The data Brahe accumulated was superior to all other astronomical measurements made until the invention of the telescope in the early 17th century. Brahe was born in Knudstrup in southern Sweden (then part of Denmark). He studied law and philosophy at the universities of Copenhagen and Leipzig; at night, however, Brahe busied himself with observing the stars. With no instruments other than a globe and a pair of compasses, he succeeded in detecting grave errors in the standard astronomical tables, and set about correcting them. In 1572 he discovered a supernova in the constellation Cassiopeia . After Brahe had spent some time traveling and lecturing, Frederick II, king of Denmark and Norway, offered to provide Brahe with funds to construct and equip an astronomical observatory on the island of Hven (now Ven). Brahe accepted the proposal,
Read more

Bunsen, Robert Wilhelm

-
. Bunsen, Robert Wilhelm (1811-1899), German chemist, who, with the German physicist Gustav Robert Kirchhoff, invented the spectroscope and discovered spectrum analysis, which led to their joint discovery of the elements cesium and rubidium . Bunsen was born in Göttingen on March 31, 1811, and was educated at the University of Göttingen. Between 1836 and 1852 he taught successively at the Polytechnic Institute in Kassel and at the universities of Marburg and Breslau; thereafter he was professor at the University of Heidelberg until his retirement in 1889. Considered one of the greatest chemists in the world, Bunsen discovered (1834) the antidote that is still used today for arsenic poisoning: hydrated iron oxide. His research on the double cyanides confirmed the principle in organic chemistry that the nature of a compound depends on the radicals composing it. Contrary to popular belief, he had little to do with the invention of the Bunsen burner , a gas burner used in scientific lab
Read more