|
Fleming's Right Hand Rule
In electromagnetism, Fleming's right-hand rule (for generators) shows the direction of induced current when a conductor attached to a circuit moves in a magnetic field. It can be used to determine the direction of current in a generator's windings. When a conductor such as a wire attached to a circuit moves through a magnetic field, an electric current is induced in the wire due to Faraday's law of induction. The current in the wire can have two possible directions. Fleming's right-hand rule gives which direction the current flows. The right hand is held with the thumb, index finger and middle finger mutually perpendicular to each other (at right angles), as shown in the diagram.{{Cite book, title=Hughes Electrical & Electronic Technology, last=Hughes, first=Edward, date=5 April 2016, publisher=Pearson Education Limited, isbn=978-1-292-09304-8, edition=12th, pages=145 * The thumb is pointed in the direction of the motion of the conductor relative to the magnetic field. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Finger
The middle finger, long finger, second finger, third finger, toll finger or tall man is the third digit of the human hand, located between the index finger and the ring finger. It is typically the longest digit. In anatomy, it is also called ''the third finger'', ''digitus medius'', ''digitus tertius'' or ''digitus III''. In Western countries, The finger, extending the middle finger (either by itself, or along with the index finger The index finger (also referred to as forefinger, first finger, second finger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms) is the second digit of a human hand. It is located between the thumb and the mid ... in the United Kingdom: see V sign) is an offensive and obscene gesture, widely recognized as a form of insult, due to its resemblance of an Erection, erect penis, It is known, colloquially, as "flipping the bird", "flipping (someone) off", or "giving (someone) the finger". The middle finger is ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Mnemonics
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for scientific reasoning is tens of thousands of years old. The earliest written records in the history of science come from Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Ambrose Fleming
Sir John Ambrose Fleming FRS (29 November 1849 – 18 April 1945) was an English electrical engineer and physicist who invented the first thermionic valve or vacuum tube, designed the radio transmitter with which the first transatlantic radio transmission was made, and also established the right-hand rule used in physics. He was the eldest of seven children of James Fleming DD (died 1879), a Congregational minister, and his wife Mary Ann, at Lancaster, Lancashire, and baptised on 11 February 1850. A devout Christian, he once preached at St Martin-in-the-Fields in London on evidence for the resurrection. In 1932, he and Douglas Dewar and Bernard Acworth helped establish the Evolution Protest Movement. Fleming bequeathed much of his estate to Christian charities, especially those for the poor. He was a noted photographer, painted watercolours, and enjoyed climbing the Alps. Early years Ambrose Fleming was born in Lancaster and educated at Lancaster Royal Grammar School, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mnemonic
A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imagery as specific tools to encode information in a way that allows for efficient storage and retrieval. Mnemonics aid original information in becoming associated with something more accessible or meaningful—which, in turn, provides better retention of the information. Commonly encountered mnemonics are often used for lists and in auditory form, such as short poems, acronyms, initialisms, or memorable phrases, but mnemonics can also be used for other types of information and in visual or kinesthetic forms. Their use is based on the observation that the human mind more easily remembers spatial, personal, surprising, physical, sexual, humorous, or otherwise "relatable" information, rather than more abstract or impersonal forms of informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Motors
An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on the motor's shaft. An electric generator is mechanically identical to an electric motor, but operates with a reversed flow of power, converting mechanical energy into electrical energy. Electric motors can be powered by direct current (DC) sources, such as from batteries, or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be powered by AC or DC, be brushed or brushless, single-phase, two-phase, or three-phase, axial or radial flux, and may be air-cooled or liquid-cooled. Standardized motors provide c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fleming's Left-hand Rule
Fleming's left-hand rule for electric motors is one of a pair of visual mnemonics, the other being Fleming's right-hand rule (for generators). They were originated by John Ambrose Fleming, in the late 19th century, as a simple way of working out the direction of motion in an electric motor, or the direction of electric current in an electric generator. When current flows through a conducting wire, and an external magnetic field is applied across that flow, the conducting wire experiences a force perpendicular both to that field and to the direction of the current flow (i.e they are mutually perpendicular). A left hand can be held, as shown in the illustration, so as to represent three mutually orthogonal axes on the thumb, fore finger and middle finger. Each finger is then assigned to a quantity (mechanical force, magnetic field and electric current). The right and left hand are used for generators and motors respectively. Conventions * The direction of the mechanical force is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Potential
The electric potential (also called the ''electric field potential'', potential drop, the electrostatic potential) is defined as the amount of work energy needed to move a unit of electric charge from a reference point to the specific point in an electric field. More precisely, it is the energy per unit charge for a test charge that is so small that the disturbance of the field under consideration is negligible. Furthermore, the motion across the field is supposed to proceed with negligible acceleration, so as to avoid the test charge acquiring kinetic energy or producing radiation. By definition, the electric potential at the reference point is zero units. Typically, the reference point is earth or a point at infinity, although any point can be used. In classical electrostatics, the electrostatic field is a vector quantity expressed as the gradient of the electrostatic potential, which is a scalar quantity denoted by or occasionally , equal to the electric potential energy o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Finger
The index finger (also referred to as forefinger, first finger, second finger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms) is the second digit of a human hand. It is located between the thumb and the middle finger. It is usually the most dextrous and sensitive digit of the hand, though not the longest. It is shorter than the middle finger, and may be shorter or longer than the ring finger (see digit ratio). Anatomy "Index finger" literally means "pointing finger", from the same Latin source as '' indicate;'' its anatomical names are "index finger" and "second digit". The index finger has three phalanges. It does not contain any muscles, but is controlled by muscles in the hand by attachments of tendons to the bones. Uses A lone index finger held vertically is often used to represent the number 1 (but finger counting differs across cultures), or when held up or moved side to side (finger-wagging), it can be an admonitory gesture. Wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of atoms and molecules. Electromagnetism can be thought of as a combination of electricity and magnetism, two distinct but closely intertwined phenomena. In essence, electric forces occur between any two charged particles, causing an attraction between particles with opposite charges and repulsion between particles with the same charge, while magnetism is an interaction that occurs exclusively between ''moving'' charged particles. These two effects combine to create electromagnetic fields in the vicinity of charge particles, which can exert influence on other particles via the Lorentz force. At high energy, the weak force and electromagnetic force are unified as a single electroweak force. The electromagnetic force is responsible for many o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thumb
The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb is ''pollex'' (compare ''hallux'' for big toe), and the corresponding adjective for thumb is ''pollical''. Definition Thumb and fingers The English word ''finger'' has two senses, even in the context of appendages of a single typical human hand: # Any of the five terminal members of the hand. # Any of the four terminal members of the hand, other than the thumb Linguistically, it appears that the original sense was the first of these two: (also rendered as ) was, in the inferred Proto-Indo-European language, a suffixed form of (or ), which has given rise to many Indo-European-family words (tens of them defined in English dictionaries) that involve, or stem from, concepts of fiveness. The thumb shares the following with each of the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Faraday's Law Of Induction
Faraday's law of induction (briefly, Faraday's law) is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (emf)—a phenomenon known as electromagnetic induction. It is the fundamental operating principle of transformers, inductors, and many types of electrical motors, generators and solenoids. The Maxwell–Faraday equation (listed as one of Maxwell's equations) describes the fact that a spatially varying (and also possibly time-varying, depending on how a magnetic field varies in time) electric field always accompanies a time-varying magnetic field, while Faraday's law states that there is emf (electromotive force, defined as electromagnetic work done on a unit charge when it has traveled one round of a conductive loop) on the conductive loop when the magnetic flux through the surface enclosed by the loop varies in time. Faraday's law had been discovered and one aspect of it (transformer emf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.svg "Click for more on -> Mnemonic")
