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Electrical Engineering

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Parent Category: Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.

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Really oversimplifying it: an electromagnet converts electric current to a magnetic field and an electric generator converts mechanical rotation to an electric voltage. An electromagnet has no moving parts while an electric generator is composed of a stationary part called the "stator" and a rotati…
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At high voltage the resistance of the supply cables has less of an effect therefore the power can be sent over long distances and then transformed back down to normal voltages.
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The insulators used on high tension transmission lines and on distribution lines are made of either glass or ceramic shaped in a mold. On high tension lines several are typically stacked to create a compound insulator that can avoid arcing at the voltage on the lines.
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The DC motor acts as a generator. The electricity generated can be used to power the overhead (or third rail) line and used by other trains going up a hill, thus acting as a brake slowing the train going downhill.
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16 gauge wire is rated: chassis wiring - 22 amperes power wiring - 3.7 amperes
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Because of high study demand
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That varies depending on the computer (see the label on your computer for its ratings): a very tiny desktop computer that I have draws about 1A an old quadcore desktop computer that I have draws about 12A etc.
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A real "electric motor" doesn't - but those things called electric motors are really magnetic motors.
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Because they are silicon controlled rectifiers, in other words a diode you can turn on (you can't turn them off, this happens when the voltage passes through zero). Therefore if you only use one you would end up with half wave a.c. This means you can't reach full power. Using a second one to control…
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An un-interruptable power supply (UPS) - provides power to equipment if the mains supply fails. It allows (for example) computer-users to finish the work they're doing, and close down the computer properly.
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Porcelain is an insulator, its resistance approximates infinity.
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The minimum resistance that can be made by using five resistors of 25 ohms each is 5 ohms, by placing all five resistors in parallel.
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Resistance is probably the missing word. I = e/R. If R is greater, I is less.
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You worked in the day when there was light to see and you slept at night (or watched the stars) when it was too dark to see. Torches, candles, oil lamps, gas lights, etc. provided limited and flickery light by which simple tasks could be done but reading was difficult with such lights. If you wanted…
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Because it has much higher torque at low speeds than other types of motor.
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No! Forget the units... 4400 is 2000 times larger than 2.2 is.
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Before you can understand how electrical energy is supplied by your electric company, you need to know how it is produced. A magnet and a conductor, such as a wire, can be used to induce a current in the conductor. The key is motion. An electric current is induced in a conductor when the conductor m…
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A generator or alternator that is turned by the wind turbine mechanism. Most power generation systems make electricity by turning generators or alternators (one exception is solar which is direct light to electricity conversion).
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If the transformer had a solid core it would build up eddy currents within the core possibly making the core itself rise in voltage. The laminations break up these eddy current circuits and prevent this.
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Not necessarily. The conductivity depends on what metal it is and how pure it is.
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It measures (they used to use an induction motor) the current flow AND the time it's used and shows it on a display - the voltage is assumed to be fixed. Now its all digital.
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The handle is either wood or plastic - both of which are good heat insulators - preventing the user from being burnt.
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No it is not required but they do recommend learning a language.
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No, the circuit must be closed for currents to flow through.
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Yes, if the governor failed in a way that "makes it think" the generator is always running too fast it might prevent the generator from running at all.
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Depending on the specific computer it can be anywhere from as little as a few milliwatts to hundreds of kilowatts. There is no single value, also many modern computers change the amount of power they consume depending on what they are doing at a given time (e.g. lots of calculations in the ALU incre…
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The resistance of an air gap is effectively infinite until it reaches its arcover threshold voltage; then it drops to near zero as the air in the gap ionizes. It returns to effectively infinite when the current through the gap is insufficient to keep the air ionized.
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The line and neutral are two of the phases , the third phase is formed by connecting a suitable capacitor from either of these wires to create a phase shifted third output. The only problem with this arrangement is the shift in the phase is dependant on the load and sometimes several capacitors are …
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The fuse (or circuit breaker) must open the hot line to prevent an unsafe condition resulting from voltage still being present in the circuit. The hot line could short to something and still cause a fire or it could electrocute a person. Just breaking the current loop via the neutral is not enough f…
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Without seeing the circuit involved no real answer can be given. I would guess you have a diagram of the circuit, tracing it out should answer your question.
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Doubling the length of a wire doubles the resistance value of the wire. It is equivalent to placing resistors in series where the total resistance value is the sum of all the resistors.
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Ohm's Law does not exist for magnetic circuits, only for electric circuits. The analog of Ohm's Law in magnetic circuits is called Hopkinson's Law.
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Because a negative feedback system "closes the loop" based on a temperature sensor in the tip of the iron. This makes the temperature of the iron nearly constant whether sitting idle on the stand or being used to solder a massive joint. Without this negative feedback the temperature of the open loop…
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In order to be transmitted long distances, voltage is raised. At the destination, voltage is lowered again to be used. This permits transmission for several miles, which wold not be possible at lower voltages.
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A surge protector is a device that clips off peaks of transient overvoltage spikes (surges) that appear on the powerlines from time to time. This action protects any equipment plugged into the surge protector from damage due to those spikes. If the spike is more than the surge protector is able to …
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240 volts
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AC generators (properly called "alternators") must be EXACTLY synchronized when connected together (either in parallel or series) or one will act as a motor and drain power from the other instead of adding. This can also damage the equipment. Most alternators sold to the public lack the special equ…
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The attraction/repulsion of appropriate magnetic fields.
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relays which operate by signalling alarms notifying the type of the fault
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Actually a battery is a group of cells. Sometimes a group of batteries might be called a battery bank.
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The SI derived unit of electric charge is the coulomb (C). In electrical engineering, it is also common to use the ampere-hour (Ah). In chemistry and particle physics, it is common to use the elementary particle charge (e) as a unit. Independent of units, the symbol Q often denotes charge.
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A charge in motion is usually called an electric current, but could also be called dynamic electricity (analogous to a charge at rest being called static electricity).
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Your question is very muddled and it is difficult to understand exactly what you are asking. Something is in "series" if it is connected in the circuit as a "daisy chain". Thus both loads AND batteries may be placed in series.
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It momentarily produces an inductive kick in the form of high voltage, around 1000 volts, so that the electrical discharge will pass along the column of the tube
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Incandescent lamps are nearly pure resistive loads with a power factor of 1
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Most electrical technicians do not get a salary, they are payed by the hour (which also means time and a half and double time pay for overtime hours when they are necessary).
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Ohm's Law. According to Ohm's law V = iR where V is voltage (usually measured in volts) between two points of the circuit i is current (usually measured in amperes) between two points of the circuit R is resistance (usually measured in Ohms) between two points of the circuit.
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Speed regulation in the series motor is quite poor.
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125 amps at 208V and 108 amps at 240V for a 45 kva three-phase transformer.
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Without also knowing the voltage of the circuit no answer can be given. In a 5 volt circuit a 5 ampere fuse will blow when the load is using 25 watts. In a 12 volt circuit a 5 ampere fuse will blow when the load is using 60 watts. In a 115 volt circuit a 5 ampere fuse will blow when the load is us…
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Electricity is a flow of current (moving charges) and has to flow into and out of a circuit or other object. In automotive applications, the metal body of the car is often used as part of the negative conduit. In grounded circuits for alternating current, any connection to the ground can provide a p…
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Basic transistors have three lead contacts that do have polarity . There are two kinds referred to as P-N-P (for positive-negative-positive leads) and N-P-N (for negative-positive-negative leads).
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energy/power
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The leakage flux is the magnetic flux that escapes the armature of the transformer and thus does not provide coupling from the primary windings to the secondary windings. If not minimized it can be a significant cause of energy loss and inefficiency in transformers.
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The relay's coil(s) would be a load, but the main function of a relay is to act as a switch to control power to a larger load.
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Wire without insulation is only supposed to be used for grounding purposes. It is the same as wire with green insulation. but is easier to connect to multiple outlets as it does not need stripping.
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Not if you want it to last. Already at 18 V you're running at 50% over voltage, which is likely to kill it pretty soon.
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Please check your car's owner's manual! When these powered cigar lighters they were typically protected by 20 ampere fuses, but now that they are only used to provide electric power a 10 ampere fuse is common and some cars use fuses with even a lower rating. Please check your car's owner's manual …
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Sheathed cable is multiconductor wire cable enclosed in a protective sheath. The most common material used for the protective sheath is thermoplastics. An example of sheathed cable can be seen in the image above.
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A series circuit only allows the current to follow one path. All other circuit types contain one or more parallel paths that the current would split between.
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Your question is confusing and probably reflects certain misunderstandings. But I will attempt to give an answer. household single phase line voltage is 110 VAC, 115 VAC, or 120 VAC in the US and 230 VAC in most other countries household "two phase" line voltage is 220 VAC, 230 VAC, or 240 VAC in …
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Any energy source can be used to generate electricity, but some will be more efficient, lower cost, or safer than others (however these criteria are often conflicting e.g. a low cost energy source may be less efficient and more dangerous than a higher cost energy source).
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Power wise then its the mains voltage chemical wise it batteries - Batteries can still cause fires
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That will depend on the temperature coefficient of resistance of the device, which could be positive (i.e. resistance increases with increasing temperature), negative (i.e. resistance decreases with increasing temperature), or zero (i.e. resistance is unaffected by temperature changes).
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You use a combination of Ohm's law ( V = I * R ) and the power formula ( P = V * I ). Substituting you get: P = ( I * R ) * I = I**2 * R Dividing both sides by R you get: P / R = I**2 * R / R = I**2 Taking the square root of both sides you get: SQRT( P / R) = I Swapping sides of the equals sign yo…
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Its filled with an electron.
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Sometimes the neutral is used instead of the ground/earth but it never should be. Using it that way is a violation of code and a demonstration of the laziness and irresponsibility of the person doing the wiring.
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Safety!!!! Although the neutral wire is also connected to ground/earth, it has current flowing through it and can thus easily have 20VAC (sometimes more) on it at the outlet. If this were connected to the metal housing of appliances it could cause a significant electrical shock to the user. The gr…
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teslacoil car ignition coil CRT television set flyback coil other transformers intended to produce extremely high voltages at low cost variac etc.
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You probably popped the breaker. The appliance is drawing too much current for that circuit (or is combined with too many other appliances on that circuit). Unplug it, turn the breaker back on. Try to find a different circuit to operate it on, or move other appliances to other circuits to reduce the…
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The only ways this can be done is via a motor generator or a solid state inverter. These can convert single phase power to 3 phase power, however they are generally too large and expensive for home use and motor generators are extremely noisy. In a commercial or industrial location 3 phase power is…
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The series resistance (swamping resistance and multiplier) in pressure coil circuit has many turns. So in addition to inductance seen before, there are inter-turn capacitance also. If this capacitance effect exceeds the inductance effect, a phase-shift in pressure coil current will cause an error. …
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The lightbulb.
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connect the bulb to electricity
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cutoff and saturation
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If the resistors are in series the voltage can not be divided, as it has to pass first through one then the other. The amount of current that flows through a set of resistors in series will be the same at all points and the total resistance in the circuit must be equal to the sum of all the individu…
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The best results would be obtained using a 208VAC to 220VAC step up transformer of the correct ratings. An autotransformer should be fine for this purpose and will be cheaper than a transformer with isolated primary and secondary windings.
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No, because the power dissipated in a resistor is proportional to the square of the current through the resistor but only directly proportional to the resistance of the resistor (I^2 R) and the current through the lower value resistor will be higher than the current through the higher value resistor…
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Capacitors have always been added on both power lines and telephone lines to compensate for the build up of inductive reactance in long runs of wire.
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In Singapore, a transmission company - SP PowerAssets - owns and manages the national electricity transmission system
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Use of complex numbers for circuit values (e.g. voltages, currents, reactances) is required to get correct answers for AC. The equations are the same as for DC circuits, but the numbers are complex not real. Also reactances vary with the frequency of the AC signals in the circuit.
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The eligibility on electricity supply in Singapore is depend on your monthly electricity consumption. If your monthly consumption is at least 2,000kWh and your account is "non-domestic", you are eligible. The Energy Market Authority ("EMA") approves your eligibility and deems you as a 'Contestable C…
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Voltage is a potential difference, which may be measured in volts, the volt being a unit of measure.
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A 20 amp 240 volt circuit can provide 4800 watts. 4800 watts / 6 watt per foot = 800 feet.
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The standard unit of electric energy is the Watt Hour.
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A combination of greater reliability and that most digital electric meters can be read remotely without having to have the meter man have physical access.
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Voltage is the force that causes current to flow through a circuit. In a similar way it isn't pressure that flows through a pipe - it is the fluid flowing through a pipe due to a difference in pressure at the entry and exit of the pipe that causes the fluid to flow through, no pressure flowing throu…
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Most electric motors change electrical energy into rotational mechanical energy. A few electric motors change electrical energy into linear mechanical energy.
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Voltages are stepped up for transmission to reduce the resistance loses in the wires over long distances.
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A Peltier diode is a thermoelectric device that uses the Peltier effect to transport heat between the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, w…
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Well, yes if you really have no other choice. However it will be so dim and red-orange in color as to be almost useless. It will be operating at about 1/4 of its rated power at that reduced voltage.
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The USB 3.1 specification provides for a bidirectional power capable of handling 100W.
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A parallel circuit would work better than a series circuit when there are multiple fixtures in a room that need the same amount of energy
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A coil symbol with a tap (usually close to one end, but not always).
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The Ampere (or Amp.) for large things such as a toaster, microwave or refrigerator. Most electronic devices use current measured in milliamperes (or miliamps) which measures thousanth (1/1000) of an ampere.
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