Direct current

Direct current is the unidirectional flow of an electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor such as a wire, but can flow through semiconductors, insulators, or through a vacuum as in electron or ion beams; the electric current flows in a constant direction, distinguishing it from alternating current. A term used for this type of current was galvanic current; the abbreviations AC and DC are used to mean alternating and direct, as when they modify current or voltage. Direct current may be converted from an alternating current supply by use of a rectifier, which contains electronic elements or electromechanical elements that allow current to flow only in one direction. Direct current may be converted into alternating current via an inverter. Direct current has many uses, from the charging of batteries to large power supplies for electronic systems and more. Large quantities of electrical energy provided via direct-current are used in smelting of aluminum and other electrochemical processes.

It is used for some railways in urban areas. High-voltage direct current is used to transmit large amounts of power from remote generation sites or to interconnect alternating current power grids. Direct current was produced in 1800 by Italian physicist Alessandro Volta's battery, his Voltaic pile; the nature of how current flowed. French physicist André-Marie Ampère conjectured that current travelled in one direction from positive to negative; when French instrument maker Hippolyte Pixii built the first dynamo electric generator in 1832, he found that as the magnet used passed the loops of wire each half turn, it caused the flow of electricity to reverse, generating an alternating current. At Ampère's suggestion, Pixii added a commutator, a type of "switch" where contacts on the shaft work with "brush" contacts to produce direct current; the late 1870s and early 1880s saw electricity starting to be generated at power stations. These were set up to power arc lighting running on high voltage direct current or alternating current.

This was followed by the wide spread use of low voltage direct current for indoor electric lighting in business and homes after inventor Thomas Edison launched his incandescent bulb based electric "utility" in 1882. Because of the significant advantages of alternating current over direct current in using transformers to raise and lower voltages to allow much longer transmission distances, direct current was replaced over the next few decades by alternating current in power delivery. In the mid-1950s, high-voltage direct current transmission was developed, is now an option instead of long-distance high voltage alternating current systems. For long distance underseas cables, this DC option is the only technically feasible option. For applications requiring direct current, such as third rail power systems, alternating current is distributed to a substation, which utilizes a rectifier to convert the power to direct current; the term DC is used to refer to power systems that use only one polarity of voltage or current, to refer to the constant, zero-frequency, or varying local mean value of a voltage or current.

For example, the voltage across a DC voltage source is constant as is the current through a DC current source. The DC solution of an electric circuit is the solution where all currents are constant, it can be shown that any stationary voltage or current waveform can be decomposed into a sum of a DC component and a zero-mean time-varying component. Although DC stands for "direct current", DC refers to "constant polarity". Under this definition, DC voltages can vary in time, as seen in the raw output of a rectifier or the fluctuating voice signal on a telephone line; some forms of DC have no variations in voltage, but may still have variations in output power and current. A direct current circuit is an electrical circuit that consists of any combination of constant voltage sources, constant current sources, resistors. In this case, the circuit voltages and currents are independent of time. A particular circuit voltage or current does not depend on the past value of any circuit voltage or current.

This implies that the system of equations that represent a DC circuit do not involve integrals or derivatives with respect to time. If a capacitor or inductor is added to a DC circuit, the resulting circuit is not speaking, a DC circuit. However, most such circuits have a DC solution; this solution gives the circuit currents when the circuit is in DC steady state. Such a circuit is represented by a system of differential equations; the solution to these equations contain a time varying or transient part as well as constant or steady state part. It is this steady state part, the DC solution. There are some circuits. Two simple examples are a constant current source connected to a capacitor and a constant voltage source connected to an inductor. In electronics, it is common to refer to a circuit, powered by a DC voltage source such as a battery or the output of a DC power supply as a DC circuit though what is meant is that the circuit is DC powered. DC is found in many extra-low voltage applications and some low-voltage applications where these are powered by batteries or solar power systems.

Most electronic circuits require a DC pow


Arulmolipet or Arulmozhipettai is a village in the Alangudi Panchayat, Ammapettai Block, Papanasam taluk in Thanjavur district, Tamil Nadu, India. அருள்மொழிபேட்டை, இந்தியாவின், தமிழ்நாடு மாநிலம், தஞ்சாவூர் மாவட்டம், பாபநாசம் வட்டத்தில், அம்மாப்பேட்டை ஊராட்சி ஒன்றியத்தில், ஆலங்குடி பஞ்சாயத்தில் உள்ள கிராமம் ஆகும். As per the 2001 census, Arulmolipet had a total population of 854 with 434 females; the sex ratio was 1033. The literacy rate was 71.25. "Primary Census Abstract - Census 2001". Directorate of Census Operations-Tamil Nadu. Archived from the original on 6 August 2009

Ron Dennis

Ronald Dennis CBE is a British businessman and Official British Business Ambassador for The United Kingdom. Dennis is the Global Consultant for Minsheng Investment Corporation and former owner of Absolute Taste, he is best known for his former role as owner, CEO, chairman and founder of McLaren Technology Group. Dennis was removed from his McLaren management roles in 2016 but remained a director of the company and a 25% shareholder until June 2017, when his 37-year association with the company ended. Between 1981 and 2009, Dennis was the team principal of the McLaren Formula One team, was instrumental in transforming the outfit into a regular world championship contender. Constructors' and drivers' world championships were won with Niki Lauda, Alain Prost, Ayrton Senna, Mika Häkkinen and Lewis Hamilton. In January 2007, Dennis sold half of his 30 percent shareholding in the McLaren Group to the Bahrain Mumtalakat Holding Company, leaving him with a 15 percent share. In 2009, together with co-owners Mansour Ojjeh's TAG Group and the Bahraini Mumtalakat Holding Company, bought back Daimler AG's 40 per cent shareholding in a deal, concluded in 2011.

As of January 2014, Mumtalakat held 50 percent of the Group's shares, with Dennis and Mansour Ojjeh holding 25 percent each. In May 2019, Dennis ranked 304th on the Sunday Times Rich List with an estimated wealth of £450 million. Aside from McLaren Group, he is one of six British business persons to be an official British Business Ambassador for advanced engineering and manufacturing. Dennis is a main trustee for Tommy's, a miscarriage help charity, he is the Global Consultant for the state owned China Minsheng Investment Group and the chairman for the UK Summit. With interests in foreign trade, Dennis became Chairman of the British East Asian Council in 2014. Before the merger with Louis Vuitton, Dennis was a major shareholder in the luxury watch maker TAG Heuer, along with his business partner, Mansour Ojjeh. In December 2014, he attempted to purchase 50% of McLaren Technology Company from Hamad bin Isa Al Khalifa and Ojjeh, after shareholder relations worsened, but the investment deals Dennis had arranged failed to materialise and the shareholding structure remained as before.

Dennis tried to purchase the company again in October 2016, with an estimated bid of 1.7 billion pounds sterling. However and Mumtalakat wanted Dennis out, refused his bid placing him, in November 2016, on "gardening leave" for two months. Subsequently and Mumtalakat did not renew Dennis' contract in January 2017, he retained 25% of shares in McLaren Technology Group, the title of "Company Director," and 11% of the shares in McLaren Automotive, as well as his role there as Chairman and "Company Director," until July 2017, when Dennis resigned from the company. Dennis was born and raised in Woking and studied motor vehicle engineering at Guildford Technical College, he began working for the Cooper Formula One team in 1966 as a mechanic at the age of 18 where he worked alongside lead driver Jochen Rindt. In 1968 Rindt took Dennis with him. For the 1969 season Rindt moved to Team Lotus; when Brabham chose retirement in 1971, Dennis and his colleague Neil Trundle decided to start their own team. In 1971, Rondel Racing was founded in Dennis's native Woking.

Money was at a premium though and Dennis was trying to find sponsorship. Through Ron's girlfriend, the daughter of John Phelps, director of Phelps Antique Furniture in Twickenham, one of its regular customers Tony Vlassopulos, a barrister son of a Greek shipowner, was asked to sponsor Rondel. Vlassopulos asked his friend Ken Grob, chairman of Alexander Howden, insurance brokers in London if he was interested in joining in. Grob said yes on the proviso that his young son Ian Grob could be part of the team, agreed. From that moment forward, Vlassopulos became Dennis' first sponsor. By the mid-1970s the team was enjoying considerable success in Formula Two. Rondel aspired to be more than a customer team and Dennis soon managed to find an additional backer to Grob and Vlassopulos in Motul, to help fund a Rondel F1 car. For 1974, a Ray Jessop-designed F1 car was planned but the energy crisis affected Motul's backing; however Dennis didn't have the overall fund anyway and so Trundle continued with the designed car from Jessop and Vlassopulos and Grob took over the ownership, with the car becoming the Token.

Dennis regrouped, forming a Marlboro-backed F2 team for two talented and well-sponsored drivers from Ecuador. In 1975 Dennis founded the Project Three team, his cars once again became race winners. In the late 1970s, Dennis founded Project Four Racing; this team went on to great success in Formula 2 and Formula 3, winning championships in 1979 and 1980 with Philip Morris backing. Project Four participated in the build programme for Procar BMW M1 racing cars; as his business interests became successful and lucrative, Dennis aspired to return to Formula One, hiring talented designer John Barnard to spearhead the design and development of an innovative new F1 car. Dennis's return to Formula One was well-timed; the recent poor performance of the former world championship-winning McLaren team had prompted Philip Morris executive John Hogan to initiate a takeover of the outfit by Dennis's Project Four operation. A reverse takeover, it heralded the arrival of the rebranded McLaren International operation and placed the thirty-four-year-old in full control of the outfit.

In addition to hiring Barnard to begin work on the team's revolutionary new carbon fibre composite chassis, the MP4/1, Dennis successfully recruited the P