CMC Medical

A resistor–capacitor circuit (RC circuit), or RC filter or RC network, is an electric circuit composed of resistors and capacitors driven by a voltage or current source. A first order RC circuit is composed of one resistor and one capacitor and is the simplest type of RC circuit. RC circuits can be used to filter a signal by blocking certain frequencies and passing others. The two most common RC filters are the high-pass filters and low-pass filters; band-pass filters and band-stop filters usually require RLC filters, though crude ones can be made with RC filters. The total impedance (resistance) of this circuit is the contribution from both the capacitor and resistor. From the previous section we have seen that the capacitative reactance Xc is shifted by - 90° from the perturbing voltage signal and therefore is expressed in complex form as  Xc = -j Xc The total circuit impedance is more...

Diamond crystal is a three-dimensional network of carbon atoms. All carbon atoms in the network are strongly bonded by carbon-carbon covalent bonds. Therefore diamond crystal has a highly symmetric cubic structure. The carbon atoms in diamond are precisely aligned. Thus diamond is an ideal crystal. Atoms in the crystal lattices in solids vibrate. These vibrations, called the atomic vibrations facilitate thermal conduction (transport of heat) in solids. In an ideal crystal, the lattices are so precisely aligned that they do not interact with each other. Therefore an ideal crystal conducts better than a non-ideal crystal resulting in ideal crystals having good thermal conductivity, which is a measure of heat conduction. Diamond being an ideal crystal is thus a good thermal conductor. Mobile electrons facilitate electrical conduction - flow of current in solids. There are no free mobile electrons in diamond crystal to ficilitate electrial more...

Capacitance is the ability of a body to store an electrical charge. Any object that can be electrically charged exhibits capacitance. A common form of energy storage device is a parallel-plate capacitor. In a parallel plate capacitor, capacitance is directly proportional to the surface area of the conductor plates and inversely proportional to the separation distance between the plates. If the charges on the plates are +q and -q, and V gives the voltage between the plates, then the capacitance C is given by  C = frac{q}{V}. which gives the voltage/current relationship  :I(t) = C frac{mathrm{d}V(t)}{mathrm{d}t}. Visit below links for more detailed knowledge of capacitance: http://www.studyadda.com/videos/jee-physics-lectures/capacitance/capacitance/1768 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-1/1769 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-2/1770 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-3/1771 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/energy-stored-in-capacitor/1772 http://www.studyadda.com/videos/jee-physics-lectures/capacitance/problems-on-equivalent-capacitance-4/1773Video Lecture Taught By-  Mr. Lalit Sardana (IIT-JEE,AIR 243) ,Sardana Tutorials

An early incandescent light bulb with the coils giving electrical contact to the filament inside the glass. Decades before Thomas Edison filed a patent for his electric lamp, Scotsman James Bowman Lindsay (1799-1862) produced constant electric light in what became a prototype of the modern light bulb. Building on Humphry Davy's successful yet impractical platinum incandescent light, which he developed in 1802, Lindsay managed to create a more usable form of the light bulb. Having secured a position as a lecturer at the Watt Institution in Dundee, Scotland, in 1829, Lindsay began experimenting with constant electric light. He demonstrated his invention in 1835 at a public meeting in Dundee. The light from an incandescent bulb is produced from a filament through which an electrical current is passed. Lindsay claimed that, with his light, he could "read a book at a distance of one and a half foot." This was an more...

"The English are fools... they give their children the smallpox to prevent their catching it." Voltaire, Letters on the English (c. 1778) Smallpox is believed to have first appeared around 10,000 B.C.E. Ramses V died suddenly in 1157 B.C.E.; his mummy bears scars that have a striking resemblance to those left by that scourge. Smallpox killed about a third of its victims and left many survivors scarred. But it was noted that survivors never got smallpox again. After the eldest son of China's Prime Minister Wang Dan died around 1000 B.C.E. of smallpox, Wang Dan sought a cure for it. A Daoist monk introduced the technique of variolation, a type of inoculation. Scab- coated pustules taken from survivors were ground up and blown into the nose like snuff. Reports of inoculation reached Europe in the 1700s. In London, in 1721, Lady Wortley Montague and the Princess of Wales urged that more...

“... an alien race that looked like insects... would build robots to look like themselves.. " Kevin J. Anderson Before the Waseda-Hitachi Leg II (WHL-11) biped robot was unveiled at the 1985 Tsukuba Expo in Japan, robots could roll, drag, or crawl their way around. But here was a real breakthrough. This one could walk. Developed by Hitachi in collaboration with Waseda University, Japan, and with an onboard computer and hydraulic pump, the WHL-11 was capable of static walking on a flat surface at around thirteen seconds per step. The robot was also able to turn. If a robot could walk like a human, it had been reasoned, it would be able to maneuver around objects and go up and down stairs—the applications of such a machine would be almost limitless. To do so, however, it had to have two legs, just like a person. It would also need to more...

"The privilege of making stockings for everyone is too important to grant to any individual." Queen Elizabeth I to William Lee William Lee (circa 1550-1610), a clergyman from Nottinghamshire, England, invented the stocking frame in 1589. One story suggests that he invented it to relieve his mother and sisters of the burden of knitting; another has it that a girl was showing more interest in her knitting than in him. Knitted fabrics are constructed by the interlocking of a series of loops, with each row of loops caught into the previous row. The stocking frame allowed production of a complete row of loops, held by a long bar similar to a knitting needle; a second bar opposed it, and each loop, picked up by a piece of wire, was transferred to the first bar. Lee's first machine, which produced coarse wool stockings, was refused a patent by Queen Elizabeth I. more...

"The only type of operation that could ever be universal would be an arthroplasty." John Charnley, lecture in 1959 More than 800,000 hip replacement operations are carried out globally every year. These enable their recipients to live more mobile and pain-free lives after their worn out, damaged, or diseased hip joints are replaced with artificial prostheses. It was the pioneering work of English surgeon John Charnley (1911-1982) that led to low-friction arthroplasty becoming the gold-standard procedure for hip replacement. Charnley moved from a method of compression fixation of fractures to considering actually replacing the joint during his investigations into the. best way to treat osteoarthritis and other conditions limiting hip movement. In a lecture to the East Denbigh and Flint division of the British Medical Association in 1959, he said, "In orthopedics, surgeons yearn for an easy hip operation, or, if a good operation is difficult,...[that] it should be universally more...

"The depth charge was such a successful device that it attracted the attention of the United States..." Chris Henry, Museum of Naval Fire Power The first significant use of submarines in warfare occurred during World War I, and with that came the need for anti-submarine weapons. The idea of using the destructive shockwaves of a "dropping mine" against submarines was discussed by the British Navy in 1910. However, it was not until the Commander in Chief, Sir George Callaghan (1852-1920), requested their production in 1914thatthey became a reality. It is the "D" type, developed by Herbert Taylor in 1915 at HMS Vernon Torpedo and Mine School, Portsmouth, England, that is credited with being the first effective depth charge. This was essentially a steel barrel packed with high explosive that could be detonated at preselected depths. Early depth charges were deployed simply by rolling them off racks on the stern of more...

"Nature composes some of her loveliest poems for the microscope and the telescope." Theodore Roszak, academic and historian The earliest microscope was no more than a single small lens that magnified between six and ten times. Sacharias Jansen and his father, Hans, a lens maker, experimented with combinations of lenses and realized that greater magnification could be obtained by an inversion of the telescope. Their compound microscope combined a magnifying objective lens (the one closest to the object being investigated) with an eye lens at the opposite end of a tube. A focusing device was added by the Italian Galileo Galilei. The circulation of blood through capillaries was observed by the Italian physiologist Marcello Malpighi (1624-1694). The popularity of microscopes was greatly enhanced by the publication of Micrographia (1655) by English scientist Robert Hooke. The Dutchman Anthoni van Leeuwenhoek (1632-1723) used a microscope to count the number of threads in more...