11. november 2003 - 22:03Der er
6 kommentarer og 1 løsning
Fysik: Transformation
Hejsa.
Jeg har i skolen (9. klasse) fået til opgave at udfylde to sider med teoretisk viden om transformation. Dvs. INGEN forsøg, men derimod, af hvem og hvornår blev transformationen første gang brugt, hvad er transformation og hvad bliver den brugt til i daglig dagen?
Nu skriver jeg naturligvis ikke dette spørgsmål fordi jeg ønsker at nogen skal lave denne opgave for mig - bare rolig! Jeg skriver det mere fordi jeg er temmelig på bar bund. Har nogen et kanon godt sted på internettet at finde informationer og facts? Har nogen noget andet, meget relevant, som jeg også bør komme ind på?
tranformation i hvilken sammenhæng? synes metal_hansens søgeresultater er en masse forskellig fysik.. og jeg tvivler på du skal snakke om transformation af hastigheder?
Nej, jeg taler ikke om transformation om hastigheder, det er rigtigt. Jeg taler om Induktion & Transformation. Altså, det hvor man transformerer strøm ned eller op til mindre eller større spænding. Med u-kerner og kobbertråds-spoler m/ vindinger og alt det.
en transformer benyttes primært når man ønsker at ændre spændingniveay.
Den lille sorte plastickasse på din optaderledning til mobilossen er en transformer. den transformere lysnettets 220V ned til de ca 10 volt som mobiln kan klare at få uden at brænde af. Ditto med opladerledningen til kameraer, fjernstyrede biler og en masse andre dimser.
indeni enhver elsparepære er der en transformer der transformerer den anden vej. sen sætter de 220V op til en enkelt meget stærk spændingspuls der sætter ioniseringen i lysstofrøret igang. de gammeldags lysstofrør har en lille hvid cylinder med samme funktion.
Induction (electricity), in electricity, the creation of an electric current in a conductor moving across a magnetic field (hence the full name, electromagnetic induction). The effect was discovered by the British physicist Michael Faraday and led directly to the development of the rotary electric generator, which converts mechanical motion into electric energy.
II ELECTRIC GENERATOR
When a conductor, such as a wire, moves through the gap between the poles of a magnet, the negatively charged electrons in the wire will experience a force along the length of the wire and will accumulate at one end of it, leaving positively charged atomic nuclei, partially stripped of electrons, at the other end. This creates a potential difference, or voltage, between the ends of the wire. If the ends of the wire are connected by a conductor, a current will flow around the circuit. This is the principle behind the rotary electric power generator, in which a loop of wire is spun through a magnetic field so as to produce a voltage and generate a current in a closed circuit.
III ELECTRIC TRANSFORMER
Induction occurs only if the wire moves at right angles to the direction of the magnetic field. This motion is necessary for induction to occur, but it is a relative motion between the wire and the magnetic field. Thus, an expanding or collapsing magnetic field can induce a current in a stationary wire. Such a moving magnetic field can be created by a surge of current through a wire or electromagnet. As the current in the electromagnet rises and falls, its magnetic field grows and collapses (the lines of force move outward, then inward). The moving field can induce a current in a nearby stationary wire. Such induction without mechanical motion is the basis of the electric transformer.
A transformer usually consists of two adjacent coils of wire wound around a single core of magnetic material. It is used to couple two or more a-c circuits by employing the induction between the coils. See Electric Power Systems.
IV SELF-INDUCTION
When the current in a conductor varies, the resulting changing magnetic field cuts across the conductor itself and induces a voltage in it. This self-induced voltage is opposite to the applied voltage and tends to limit or reverse the original current. Electric self-induction is thus analogous to mechanical inertia. An inductance coil, or choke, tends to smooth out a varying current, as a flywheel smooths out the rotation of an engine. The amount of self-induction of a coil, its inductance, is measured by the electrical unit called the henry, named after the American physicist Joseph Henry, who discovered the effect. The inductance is independent of current or voltage; it is determined only by the geometry of the coil and the magnetic properties of its core.
Dette kan evt. bruges? du må selv stå for at oversætte det for jeg er sq lidt træt.. :)
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