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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
A: Since you know the current flow you need the voltage drop for this particular led at 20ma. All LED require a current and voltage to operate properly assuming a voltage drop of 2v then for a 12v source it becomes 12-2=10v 10v/.02=500 ohms in series to limit the current is required
How can the phase rotation of one alternator be changed in relationship to the other alternator?
alternators will charge in either direction; they are three-phase systems fed through an internal rectifier, so it is irrelevant.
Explain the need for power consumption in CMOS circuits?
Even though it would seem that CMOS circuits require nearly zero power, that is only true when they are not doing anything, i.e. when the clock speed to zero.
When a conductor changes state, such as going from zero volts to five volts, it requires a shift in potential energy. If the conductor has capacitance, that shift requires current. Current times voltage is power. Power times time is energy. Even though the capacitance is very, very small, and the time is very, very short, energy is required to effect the change. Add to that the fact that you want to make this change very, very quickly, and that means you need more current - yes, for a shorter time - but you still need to look at power. Add up the millions and millions of conductors in a high end chip, and you see why they consume a lot of power and why they get hot - especially when you push the clock speeds.
Can friction produced by wheels of moving train generate electricity?
yes we can produce electricity by fixing dynamo in traction wheels so heat is produced when the friction of train wheel & track so the dynamo generates an power D.C SUPPLY and is converts into Ac supply so we can use that energy for electric trains use of lights and fans....
A busbar is a length of flat, rectangular-section, copper used as a common point of connection for a number of electrical conductors that share the same potential. The term has the same derivation as 'omnibus', meaning 'serving several objects', and its correct spelling is busbar or bus bar, not'bussbar'!
For DC or single-phase applications, two busbars (physically in parallel with each other) are required -one at a positive potential and the other at a negative potential (DC) or one for the line and the other for the neutral. Often a third busbar is provided for neutral conductors and a fourth for the earth (ground) conductors. For three-phase systems, three busbars are required -one per line- and, possibly, one for the neutral and yet another for the earth.
Busbars are found in a variety of places, from those operating at thousands of volts in outdoor and indoor substations, down to those operating at hundreds of volts in residential circuit-breaker panels.
What is impedance coupled amplifier?
The purpose of impedance matching is to provide for the highest efficiency between either the stages of an amplifier circuit or from a device to the amplifier for the same purpose.
Impedance matching us used to make the circuits compatible based on electrical characteristics of a particular circuit from one section (or stage) to the next.
Why does the North American grid use the 60 Hz frequency in electrical generation?
There is no reason to prefer one Hz frequency over the other. In places like Japan both 50 and 60Hz frequencies co-exist together. It is simply the way North America has used since the development of the electrical power grid and there is no reason to need to go to a 50Hz system.
Operation of booster transformers?
It is a kind of transformer used to make changes in accordance with the voltage connected to substituting current hardware. It associations are utilized as a part of a few places, for example, uninterruptible power supply units for PCs, and in the tanning bed industry....
In D.C supply the transformer is not connected why?
In a DC power supply a transformer is connected. The only time there would be no transformer used would be if the DC voltage wanted was 120 VDC. The transformer in the power supply is connected to 120 VAC on the primary side and the secondary side of the transformer is connected to either a half wave or a full wave diode bridge. The voltage out of the diode bridge will be the same output voltage potential as the transformer's secondary voltage but it will be a DC (Direct Current) potential.
Reading the question in another way, transformers are not connected in a DC circuit. The reason being is that the transformer operates on a collapsing magnetic field. This field induces a voltage into the secondary side of the transformer. Since the DC circuit does not operate on the principle of a collapsing field except when the circuit is opened, the transformer would not operate as a transformer should..
True!
c=q/v c=q/v
It is electronic device which pass or transform a electric energy from one ckt to anoher ckt
The answer is wrong. AN denotes the cooling method of Transformer. AN means Air Natural
What is longest High Voltage electric transmission line in the US?
Pacific DC Intertie, a 500KV direct-current power line from The Dalles, Oregon to Los Angeles.
What is triangular wave generator?
Triangular wave generator is a device (for eg NE555 timer) that generates a triangular wave by integrating a square wave. In applications an ICL8038 IC can be used to generate all types of waves.
What is the advantage of using a stranded copper conductor over a solid copper conductor?
It would of course depend on the specific application. Current tends to travel on the surface of a conductor and a stranded conductor has more surface area and thus offers less resistance to the current. Stranded wire also bends a bit easier than the corresponding size solid wire.
What would happen if two secondary winding were connected in parallel with the wrong polarity?
Quite simply, they supply electricity in addition to each other and each lead will be connected to the opposite polarity lead of the other winding... you have a short circuit. The transformer will rapidly get hot and if it has no thermal fuse, might start a fire or cause other damage.
How can a dlta connected motor be converted in star?
If the motor terminal has six terminals in the terminal box, then it can be connected either in delta or star. If there are only 3 terminal wires then the motor can not be connected in star.(it means that the motor is designed to be connected in delta only)
Why transformer action can take place in DC circuit?
Not clear what your question is. First of all, circuits are not classified as DC and AC. Circuits are what they are, and you can apply either AC or DC to any circuit. However, considering a circuit that was designed only for use with DC applied. Still your question is unclear. What is transformer action? "Transformer Action" happens in a transformer.
What are the two classification of lines?
The answers are:
*vertical lines
*horizontal lines
*jagged lines
*dynamic lines
