What is the difference between an active electrical element, and a passive electrical element?
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The way that I have always determined whether or not an element or even device is passive or active is whether or not that device requires a source of electricity to perform its function.  For example, a resistor, capacitor, inductor, or even diode merely takes a signal and affects it in some manner consistant with its function.  A transistor, on the other hand, requires a third input to perform its function.  This would be true for IC's like op amps as well.  This distinction can also be extended to devices such as cavity combiners would be a passive element while an amplifier would be considered active.
269316
There are many types but all work on the principle that different semiconductors (i.e conducts electricity under certain conditions) placed together can turn on larger currents in another circuit.\nThe metals usually used are Germanium, Gallium, Asenide or compound of these including Silicon and Aluminium.\nYou might want to look at http://en.wikipedia.org/wiki/Transistor for more detailed info.
689000
Induction changes the kinetic energy of shaking into electrical energy.  The electicity is stored in a capacitor (acting as a short term battery), which feeds into a LED.\n\nPS: friction is not necessary, in fact the less friction the better.
516803
Active transport requires energy (like from ATP) and passive transport does not require any outside energy.
81351
they have the same polarity whence there is no dynamic current, just a static electricity
8457
Amp is a measure of current, which is HOW MUCH electricity flows. There is a relation that can be found between an AMP and how many electrons per unit time.\nVolt is a measure of electric FORCE.\n\nSo, with more FORCE, you can push MORE electrons through a restriction, OHMS.
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(m)\n\nA detection device that requires input energy from a source other than that which is being sensed. Note: An example of an active sensor is a photoconductive cell. 2. In surveillance, a detection device that emits energy capable of being detected by itself. Note: An example of an active sensor is a measuring instrument that generates a signal, transmits it to a target, and receives a reflected signal from the target. Information concerning the target is obtained by comparison of the received signal with the transmitted signal. 3. A measuring instrument in the Earth exploration-satellite service or in the space research service by means of which information is obtained by transmission and reception of radio waves.
94937
Department stores will/are using Passive RFID tags:\nPassive RFID tags operate without a separate external power source and obtain operating power generated from the reader. Passive tags are consequently much lighter than active tags, less expensive, and offer a virtually unlimited operational lifetime. The trade off is that they have shorter read ranges than active tags and require a higher-powered reader. Read-only tags are typically passive and are programmed with a unique set of data (usually 32 to 128 bits) that cannot be modified. Read-only tags most often operate as a license plate into a database, in the same way as linear barcodes reference a database containing modifiable product-specific information.\n\nRFID systems are also distinguished by their frequency ranges. Low-frequency (30 KHz to 500 KHz) systems have short reading ranges and lower system costs. They are most commonly used in security access, asset tracking, and animal identification applications. High-frequency (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) systems, offering long read ranges (greater than 90 feet) and high reading speeds, are used for such applications as railroad car tracking and automated toll collection. However, the higher performance of high-frequency RFID systems incurs higher system costs
51700
Definitions of inductance on the Web:\n\n    * The property of a circuit or circuit element that opposes a change in current flow, thus causing current changes to lag behind voltage changes. It is measured in henrys.\n      http://www.birnbach.com/TechnicalInformation/glossary/I.htm\n\n    * The property of an electric circuit that opposes a change in current flow.\n      http://www.customautosounds.com/faq.html\n\n    * (L) In general, the ability of a conductor to produce a magnetic field. In particular, magnetic flux divided by current, measured in henries (H). L=F/I. Or, the voltage (back emf) a conductor generates divided by rate of change of current in that conductor (self inductance) or another conductor (mutual inductance). L= -V/(dI/dt), where dI/dt is the rate of current change.\n      http://www.rcmicroflight.com/library/glossary.asp
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AC in and DC out.\n\nA diode only allows current to flow in one direction and blocks it if it is wrong.\n\nthe diodes in the bridge are connected together so that the +V current flows in One direction. the bridge .....( I cant be bothered)\n\nwikipedia has the answer...\n\nhttp://en.wikipedia.org/wiki/Bridge_rectifier
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Static electricity is simply the result of positive and negatively charged ions. Depending on the charge, these ions repel and attract each other.\nMany electronic parts are made by incorporating microscopic connections to different points within the component. Static electricity can destroy these connections rendering the part useless.\nWe defend against discharge by grounding ourselves before touching any devices or using materials that reduce the ability of the charge to build.\nAnti-static spray works by neutralizing the ions of an item such as clothes, hair, carpets, and other items. It also works by attracting moisture out of the air, increasing the conductive properties of the material the product was sprayed on.
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The inductor stores the energy in electromagnetic form. The capacitor stores it in electrostatic form. The resistor while dissipate it in heat form.\nIn an inductor when electric current is flown the magnetic field is formed in the coil due to Ampere'law. The magnetic domains in the core material are aligned accoring to magnetic field of coil. This takes energy from elctric current flowing to align themselves and is stored as magnetic enrgy.\nIn Capacitor when it is connected to a voltage source, the charges flow in to its large area electrodes to build an electric field across the insulator between electrodes. Here also the electric energy is stored in the insulator to align its dipoles according to electric field.\nIn resistor the current flowing increases the vibration of molecules of material as there are less free electrons to support current flow.
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An active filter is a type of analog electronic filter, distinguished by the use of one or more active components i.e. voltage amplifiers or buffer amplifiers. Typically this will be a vacuum tube, transistor or operational amplifier.\n\nThere are two principal reasons for the use of active filters. The first is that the amplifier powering the filter can be used to shape the filter's response, e.g., how quickly and how steeply it moves from its passband into its stopband. (To do this passively, one must use inductors, which tend to pick up surrounding electromagnetic signals and are often quite physically large.) The second is that the amplifier powering the filter can be used to buffer the filter from the electronic components it drives. This is often necessary so that they do not affect the filter's actions.\n\nPassive filters:\n\nSingle pole types:\nThe simplest electronic implementations of linear filters are based on combinations of resistors, inductors and capacitors. These filters exist in so-called RC, RL, LC and RLC varieties. All these types are collectively known as passive filters, because they do not depend upon an external power supply. Inductors block high-frequency signals and conduct low-frequency signals, while capacitors do the reverse. A filter in which the signal passes through an inductor, or in which a capacitor provides a path to earth, therefore presents less attenuation to low-frequency signals than high-frequency signals and is a low-pass filter. If the signal passes through a capacitor, or has a path to ground through an inductor, then the filter presents less attenuation to high-frequency signals than low-frequency signals and is a high-pass filter. Resistors on their own have no frequency-selective properties, but are added to inductors and capacitors to determine the time-constants of the circuit, and therefore the frequencies to which it responds.\n\nAt very high frequencies (above about 100 megahertz), sometimes the inductors consist of single loops or strips of sheet metal, and the capacitors consist of adjacent strips of metal. These are called stubs.
892848
One of the most frequently used is E=IR    ;E =voltage    I=current   R= resistance. U can change this every way depending on the unknown.\n    Good luck
1115026
Voltage is simply the potential electrical "pressure" of a circuit.  Current is the actual flow of electrons, so that's what's felt.  Think of it in terms of water & pipes.  You feel the water flow, not the potential pressure behind it.  If there is more resistance (smaller pipes, more valves), the potential pressure of the water doesn't change, but the flow is reduced.
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Electricity is  flow of electrons in a conductive material like copper or any metals.  The atoms in the conductor are passing the electrons to the next atom in sequence (current flow in Ampere unit). \n\nAnalogy: \nYou can imagine people in line, passing balls in sequence to the next person until the balls reached the other end.\n\nThe force behind the movement of electrons (potential difference in Volt unit), is due to the excessive supply of electron (negative) from one end and lack of supply (Positive) from the other end. (They flow downstream like water).\n\nImagine if you connect two ends of wire to the positive and negative side of the battery. (But don't do it. That is called; short circuit)\n\nIf the wire is cut in the middle and you connect a light bulb between the two cut ends, The light bulb will glow. \n\nHere is the reason;\n\nBecause the light bulb filament (also a metal but doesn't melt easily) is smaller than the wire conductor and does not easily allow the passage of electron (resistance in Ohm unit), The flow of electron will be restricted to a certain amount (like a bottleneck in a pipe) this restriction will cause heat and light due to friction.\n\nMy best tailored answer for you ;=)
1136306
the electricity produced by rubbung two surfaces is static electricity ie it cannot move .it is created when some electrons from on surface are transferred onto the other surface .therefore the surface that has acquired electrons gains a negative charge whereas the other surface acquires an equal and opposite positive charge due to loss of electrons