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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
What are the objectives in short circuit study?
To provide the data necessary to design protection systems.
Why you are giving dc supply for biasing the amplifier why not ac?
The purpose of biasing an amplifier is to shift its operating point, so that when you apply a signal in you will get a expected signal out. The operating point is generally in the middle of the linear region. You would not use AC for the bias, as that would cause the operating point to constantly shift, and you would then not be able to differentiate between the signal and the bias.
How do you relate AC and DC voltage by means of complex numbers?
A complex number is a combination of real and imaginary numbers. An example of a complex number is the expression (a + jb), in which the letter j is called an 'operator'. In this example, the operator +j indicates that the quantity b is acting at an angle of +90o to quantity a -or is 'leading' a by 90o. If the operator was -j, then it would be indicating that quantity bis acting at -90o to quantity a -or is 'lagging' a by 90o.
Mathematicians use the letter 'i' to represent an imaginary number, but in electrical engineering we use the letter 'j'. This is because we already use a lower-case 'i'to represent an instantaneous value of current. In mathematics, the operator is sometimes written after the quantity to which it applies (i.e. 'bj'), but it is more usual, in engineering, to place the operator in front of that quantity (i.e. 'jb').
The application of the operator 'j' to a phasor, then, acts to rotate that phasor, counterclockwise, through 90 degrees.
The term, 'imaginary', is misleading -it doesn't mean that it exists only in the mind! It is simply a mathematician's term for 'quadrature', meaning 'lying along the y-axis'.
A.C. quantities, such as current and voltage, can be resolved into horizontal and vertical components. So, we can represent an alternating-current quantity by a complex number which represents its in-phase component together with its quadrature (plus or minus 90o) component. For example, 3+j4 could represent a 5-A current, whose in-phase component is 3 A, and whose quadrature component is 4 A (i.e. which leads the in-phase component by 90o).
Complex numbers enable complex a.c. circuits to be resolved relatively easily, and without the need to construct complicated phasor diagrams.
As in-phase and quadrature ('imaginary') components only apply to a.c. quantities, we do not need to apply complex numbers to d.c.
What happens if a megger test fails?
If a megger test fails you have a short between the two wires or the wire to ground that you are testing. This short circuit has to be repaired before the equipment is placed back into service.
Does ohns law state that the current equals amperes divided by the restitance?
No, it doesn't! Ohm's Law states that 'the current passing through a conductor is proportional to the voltage applied across the ends of that conductor, providing external conditions such as temperature remain constant'. Put another way, Ohm's Law can be expressed as 'the ratio of voltage to current is constant for variations in voltage'.
In fact, very few conductors obey Ohm's Law, so that it is by no means a universal law. Those that do are called 'linear' or 'ohmic' materials, whereas those that don't are called 'non-linear' or 'non-ohmic'. Non-linear conductors include tungsten, and non-linear devices include semiconducting materials including diodes.
The ratio of voltage to current is called resistance, so you can always determine the resistance of a material, at any given voltage, by dividing that voltage by the current -whether that material obeys Ohm's Law or not.
Use a voltmeter with a high input impedance and measure at the source the voltage.
How do you attach a wheel to an electric motor?
eat it 4 times, not 3 times, not 5 times, 4 times! make sure mamadou licks ur grammy!! and eat a colored waffle
Its not load-shading. Its Load Shedding.. It happens when there's a lack of power, and the industries require more power, the government transfer the elecricity from residential areas for a while to provide for the industries
This is a WAG from a power boater, not a sailboater, but...I think there are two things to consider. (assuming you don't have remote controls for your kicker) First, how accessible is the outboard? If the outboard is so far aft of the cockpit that you can't reach the tiller (or wheel) then you will need to be with the engine for forward/reverse control and speed control. On the other hand, if your outboard is close enough to the rudder control to use it, the rudder has much greater surface area and you would have more steering control using the rudder. Just an educated guess. Good luck. From a sailor- On my boat I steer by rudder and leave the motor amidships for normal motoring But the outboard, with its directional thrust, is very handy when in tight quarters especially at low speeds when the rudder is less effective. I have an extension for the motor control handle to make it easily accessible from the cockpit.
This statement is correct
How does voltage and current affect resistance?
No, resistance is not affected by either voltage or current. Reading the various answers to similar questions on this topic, there seems to be a misunderstanding of Ohm's Law in which people think that, because R = V/I, then a change in either voltage or current must cause a change in resistance. This is most definitely not the case. This is because resistance is the constant of proportionality in the equation. The equation, quoted, merely tells us what the resistance of the circuit happens to be for a given ratio of voltage and current.
Resistance is only affected by the length, cross-sectional area, and resistivity of the conductor. Because resistivity is affected by temperature then, indirectly, temperature also affects resistance. So, if the current flowing through a conductor causes its temperature to change, then so, too, will its resistance -but, it is the temperature that is causing the change in resistance, not the current.
Discuss why the damper winding are not used in turbo generator?
It is definitely used in a turbo-generator
Does a transformer increase amps?
The primary current is determined by the secondary current, not the other way around. For example, a step up transformer will step up the primary voltage in proportion to the turns ratio of the transformer. Any secondary current is then determined by the secondary voltage and the load, NOT by the primary current. The primary current is then determined by the secondary current in proportion to the reciprocal of the turns ratio.
What meter range to measure unknown voltage?
Always start with the highest scale, than work your way down until you get a midscale reading. If you start with a low scale, you will overrange the meter, which can damage it in severe cases (especially the older analog meter movements).
Why do the cell-phones use higher frequency bands Ghz and not lower ones Khz-Mhz?
The lower bands are already in use, and have been for many years. Additionally, the higher frequencies allow the use of very small antennas and some other components that reduce the size of the phones. Microcircuits for microwaves.
Explain Transmission and distribution systems?
see URL below.
Or go to the library. You are asking for something that requires many books to explain.
Will a 15000 kw transformer power a 2500sqft house?
A 15000 KW transformer will power a small city! One KW is one thousand watts, so 15000 KW is 15,000,000 watts. The average 2500 ft2 house in the US uses somewhere between 24000 and 48000 watts maximum (thats a 100A or 200A service). Did you perhaps mean 15000 watts? That would correspond to a 60A service, which is pretty small. If you have gas appliances (stove, furnace, water heater, clothes dryer) and no big electrical appliances, such as an air conditioner, then maybe a 60A service would do. Most jurisdictions require a minimum 100A service these days except in unusual situations, such as mobile homes and such. A house that size should have a 200A 42 circuit panel. This relates to a 50Kva transformer
What is the meaning of locational mobility of entrepreneurs?
Moving and settlement is in human nature but some communities are more mobile than others. Only few of the entrepreneurs are mobile. Their locational mobility depends upon availability of raw material and labor, experience, socio political information, etc.
What are the feature that effect the frequency response of an amplifier?
all reactive elements in the amplifier, including stray capacitances and inductances.
Who is the father of Electronics?
Michael Faraday(1791-1867)----Electronics
Claude Shannon(1916-2001)---Information theory
Ohmic decay is the wasting away of dipolar magnetic fields. This decaying takes place over a very long period of time.
If certain conditions exist current levels as low as can be fatal?
Current as low a one milliampere at 60 hertz, applied directly across the heart, can cause irreversible ventricular fibrillation.
