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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
How many alternations make up one cycle of an alternating current?
Frequency in Hertz is a count of cycles per second. So at 60Hz, there are 60 cycles per second. This means there are (60 cycles per second x 60 seconds) = 3600 cycles per minute.
The process of separating the original information or SIGNAL from the MODULATED CARRIER. In the case of AMPLITUDE or FREQUENCY MODULATION it involves a device, called a demodulator or detector, which produces a signal corresponding to the instantaneous changes in amplitude or frequency, respectively. This signal corresponds to the original modulating signal
When is electrical energy transferred?
Through conduction and induction. Electrons stay generally in the same place while the energy is imparted through the wire. Resistors and capacitors deal with electricity in their own ways. Caps store and discharge energy while resistors can set voltage levels and current flow. In a transformer, two coils on a metal frame can impart their energy on one another, actually transfer it. This happens through the magnetic fields described by Faraday. The active elements in electronics are numerous but few effect the flow of electricity more than the modern transistor. It has almost totally supplanted the tube as a control device. The transistor can control large amounts of current in its' different iterations, the SCR, Triac, FET, IGT, etc.
What is a Temperature measuring devices?
you can stick a thermometer up your booty and see what happens but i think it will hurt if you push it up to high
What is the phase shift between voltage and current when an capacitance is connected to the circuit?
The amount of phase shift depends on the resistance that is also present in the system. In an ideal situation, the phase shift would be +90 degrees, but that would require a voltage source with zero resistance, conductors with zero resistance, and an ideal capacitor that exhibited only capacitance.
What is the function of a dielectric?
The function of a dielectric is to be the support between to conductive components. It has nothing to do with the action taking place, but buffers the area in which the action is taking place.
Can you use transistor as diode?
its the simplest thing to do. There are three legs in a transistor, one each of collector, base and emitter. So if you need to use it as a diode, just connect either collector-base or emitter-base. Say, if you use an NPN transistor, then the base region will be the anode of diode and emitter or collector will be the cathode of the diode.
Is there any new symposium names for electrical engineering?
The most important Electrical Engineers organization in the world is INTERNATIONAL ELECTRICAL AND ELECTRONIC ENGINEERING Society (IEEE).
On the organization site (can be found easily with Google) all the most important symposiums in this field are listed with a detailed summary of the considered subjects.
On the same site it is also possible to find a list of the most important peer review scientific journals in the fields of electrical engineering, electronics telecommunications and software.
How do you Calculate Pumping Cost using Horse Power and also Amp's?
Horse-power: convert that to kilowatt. Multiply by the time in hours you have the pump on, to get kilowatt-hours. Multiply the result by the cost of each kilowatt-hour. (Look at a recent electricity bill - if it doesn't explicitly state the cost per kilowatt-hour, you can divide the total of the bill by the number of kilowatt-hours consumed.)
Amperes: You would also need the voltage. If you multiply amperes by volts, you get the power in watts. Divide the result by thousand to get kilowatts. Then continue as above.
CommentAs the horsepower quoted for a machine is always its output power, you will need to know the efficiency of the machine in order to determine the input power (in watts), before performing the above calculations. The input power is always higher than the output power. Efficiency varies according to (a) the power rating of the motor, and (2) the actual load it is supplying, and can be less than 80% for smaller motors.
Why transformer rating is mentioned in kva rather than kw?
Because its measured in kilo volt amps which is the actual reflection of current flowing through the windings.
if kw were used as a rating, then it would have to be stated at some power factor
Why is an ordinary transistor known as a bipolar transistor?
because once saturated it will conduct current both way
raja TOQEER (Pakistan)
How do you solve the total resistance in series-parallel connection?
One step at a time...
RSeries = SummationI=1toN (RI)
RParallel = 1 / SummationI=1toN (1 / RI)
Simply solve what you know, and build on the results.
What will happen rated voltage applied in transformer short circuit?
I can only answer this from an actual problem I had in relation to the question.
20-60VA 12V transformer supplying 2x20W lamps,both lamps had blown,so I bought 2x10W replacement lamps.
On replacing the lamps,when I fitted the first and tried to power up,the lamp glowed briefly,then went out.
It was only when I fitted the second lamp that both fittings lit up continuously,so in brief,the answer to the question is................the load won't operate.
AnswerThe power rating of a load should never exceed the volt ampere rating of the transformer, otherwise the resulting load current may overheat the transformer. So the situation you describe is perfectly normal.
The reason for the problem encountered by the writer of the original answer is not clear. A 60-V.A transformer should supply two 20-W lamps without any difficulty whatsoever. I suspect that the problem had nothing to do with the power rating of the lamps vs that of the transformer, and more to do with the voltage. For example, was the secondary voltage of the transformer higherthan the rated voltages of the lamps? If so, then the lamps would have burnt out.
What does a coil do in a circuit?
it convers 12 volts into 50,000 volts
Coil in electronics means wire wrap around some media the get different uses in applications. The above answer only pertains to coil on a car I suppose
It is part of the ignition system. in older cars, it is a single unit that is about the size of a coke can. In many newer cars, you have individual coil packs sitting on top of each spark plug.Megger test
On the whole megger testing is non destructive. What happens is a DC voltage is applied to the device or winding under test. It is an insulation test to see is the insulation has been injured in any way to cause a short circuit when normal power is applied to it. On my megger there are 3 ranges 300V, 750V, and 1000 volts. Applying the proper voltage is essential to not damaging the device you are testing. Working voltages up to 240 volts should use the 300 range. Working voltages up to 600 volts use the 750 volt range and working voltages above 600 use the 1000 volt range. As you can see if you used the 1000 volt range on a device that had a working voltage of say 24 volts you could damage the insulation just by testing it. So meggering a device is non destructive if you use the tester as its instructions tell you to.
What should we do to increase the capacitance of a capacitor?
Not much if it is a fixed capaitor. If it is a variable capacitor, rotating the shaft to mesh the two sets of plates more closely will increase the capacitance.
Ionised particles are particles that carry a positive or negative charge. This is due to the loss or gain of an electron or electrons. Losing an electron will cause a particle to become more positively charged, while gaining an electron will cause a particle to become more negatively charged.
Can you run a 12 volt ac water pump with a 12 volt dc adapter?
No. You need 12 volt AC to run a 12 volt AC motor, not 12 volt DC.
What precaution one must take while measuring AC on DMM?
1. Digital multimeters are very high impedance, they therefore draw very little current from the circuit under test. This makes them very sensitive to stray voltages. A voltage reading may not neccessarily mean that there is a useful voltage available on the circuit under test. Take readings other than expected, with a pinch of salt. Understand the circuit under test.
2. A varying, or fluctuating voltage on the circuit under test, is not easy to see from digits. The numbers may just appear to change at random, whereas with an analogue meter, a pulse or variation will be easy to see from the needle movement.
How do you convert kilowatt-hours to megawatt-hours?
There is no conversion factor between these two units of measurement, as they are measuring completely different quantities. It's a little like asking how you would convert kilometres per hour into furlongs... with an added complication thrown in (i.e. the vehicle is going sideways as well as forward!).
A kilovolt ampere (correct symbol: kV.A) measures the apparent power of a load, whereas a kilowatt hour (correct symbol: kW.h) measures the work done by a load.
If you knew the power factor of the load, then you could use the apparent power to determine the true power (in kilowatts), then determine how much work is done over a given period of time.
In relation to electric what does the term fault protection mean?
Protective devices - relays, CT,PT, isolators, circuit breakers are used for fault protection. Fault protection means If there is a fault in the circuit, the circuit must be cut off before any damage occurs due to fault.
What are the applications of Eigenvalue and eigenvector in Engineering?
Have you ever seen the video of the collapse of the Tacoma Narrows Bridge? The Tacoma Bridge was built in 1940. From the beginning, the bridge would form small waves like the surface of a body of water. This accidental behavior of the bridge brought many people who wanted to drive over this moving bridge. Most people thought that the bridge was safe despite the movement. However, about four months later, the oscillations (waves) became bigger. At one point, one edge of the road was 28 feet higher than the other edge. Finally, this bridge crashed into the water below. One explanation for the crash is that the oscillations of the bridge were caused by the frequency of the wind being too close to the natural frequency of the bridge. The natural frequency of the bridge is the eigenvalue of smallest magnitude of a system that models the bridge. This is why eigenvalues are very important to engineers when they analyze structures. (Differential Equations and Their Applications, , pp. ).
Car designers analyze eigenvalues in order to damp out the noise so that the occupants have a quiet ride. Eigenvalue analysis is also used in the design of car stereo systems so that the sounds are directed correctly for the listening pleasure of the passengers and driver. When you see a car that vibrates because of the loud booming music, think of eigenvalues. Eigenvalue analysis can indicate what needs to be changed to reduce the vibration of the car due to the music.
Eigenvalues can also be used to test for cracks or deformities in a solid. Can you imagine if every inch of every beam used in construction had to be tested? The problem is not as time consuming when eigenvalues are used. When a beam is struck, its natural frequencies (eigenvalues) can be heard. If the beam "rings," then it is not flawed. A dull sound will result from a flawed beam because the flaw causes the eigenvalues to change. Sensitive machines can be used to "see" and "hear" eigenvalues more precisely.
Oil companies frequently use eigenvalue analysis to explore land for oil. Oil, dirt, and other substances all give rise to linear systems which have different eigenvalues, so eigenvalue analysis can give a good indication of where oil reserves are located. Oil companies place probes around a site to pick up the waves that result from a huge truck used to vibrate the ground. The waves are changed as they pass through the different substances in the ground. The analysis of these waves directs the oil companies to possible drilling sites.
Eigenvalues are not only used to explain natural occurrences, but also to discover new and better designs for the future. Some of the results are quite surprising. If you were asked to build the strongest column that you could to support the weight of a roof using only a specified amount of material, what shape would that column take? Most of us would build a cylinder like most other columns that we have seen. However, Steve Cox of Rice University and Michael Overton of New York University proved, based on the work of J. Keller and I. Tadjbakhsh, that the column would be stronger if it was largest at the top, middle, and bottom. At the points of the way from either end, the column could be smaller because the column would not naturally buckle there anyway.
Does that surprise you? This new design was discovered through the study of the eigenvalues of the system involving the column and the weight from above. Note that this column would not be the strongest design if any significant pressure came from the side, but when a column supports a roof, the vast majority of the pressure comes directly from above.
Ready to parlay your knowledge of linear algebra into fame and fortune? Read "The 25,000,000,000 Eigenvector: The Linear Algebra Behind Google". (the seventh link below)
