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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 series RC circuit will have a phase shift between 0 and 90 degrees?
If there are only a resistor and a capacitor in the circuit, then the phase shift will indeed be between 0 and 90 degrees. When the resistor and capacitor are in series, the phase shift will be negative when the capacitor is connected to a source voltage and the resistor is the load. The phase shift will be positive when the resistor is connected to the source. The lower the values of R and C, the higher the frequency bandwidth.
With the resistor and capacitor connected in series and the two parts connected to a current source, the phase shift will be negative. At high frequencies, the output voltages is lower, and the circuit appears as a very low impedance. At low frequencies, the circuit looks more like a resistor. Again, the phase shift will be between 0 and 90 degrees.
CommentThe correct term is phase angle, not 'phase shift'. By definition, the phase angle is the angle by which the load current leads or lags the supply voltage. For an RC circuit, the current leads the voltage, so the phase angle is a leading phase angle.
Single Phase 240 120 Volts AC a test meter placed across black wire and Ground wire will read what?
This is because the ground connection is a protective earth ground, not intended to carry current. Since ground and neutral are tied together at the distribution panel, you might expect them to have no potential difference, but impedance in the conductors will result in a voltage drop across neutral, biasing the voltage seen between hot and ground, as opposed to hot and neutral.
What are parameters in a circuit?
if by parameters, you mean parts, any circuit needs three things. A source, like a battery, a load, like a lightbulb, and conductors, eg. wire.
What is better uninterruptible power supply or automatic voltage regulator?
It depends on the application, and on the implementation of the UPS. Some UPS devices function as an AVR by boosting the output voltage when the input voltage sags. A UPS will also help you during a complete power outage, which an AVR will not. A UPS however has batteries which need to be periodically replaced. An AVR does not, which means less maintenance.
Why the series motor is started with some initial load?
In dc motors Speed is directly proportional to back emf and inversely proportional to flux i.e
N∝(Eb/φ)
In series motor back emf is practically constant.
So if we start motor without any load Flux will be small and so speed will be very high. if we start motor without any load it will gain very high speed and may get damaged due to centrifugal forces.
Series motor have very high starting torque and used where high starting torque is required.
Why Vacuum circuit breaker is using HT and why Air circuit breaker is using in LT?
Dielectric Strength of Vacuum is more than that of Air. In HT voltage is more than LT. So VCB is used in HT & ACB in LT.
Rakesh Gaikwad
How does good grounding in your house affect electricity bills?
'Good' grounding, or earthing, has no effect whatsoever on electricity bills. Electricity bills are based on your property's energy consumption. Grounding is simply a safety feature of the electrical system; it draws no energy.
What is the purpose of the toughening phase of PRT?
The purpose of the toughening phase is to develop foundational fitness and fundamental movement skills.
What are the reasons for conducting transformer turns ratio?
The reason for conducting transormer turns ratio is to determine if the transformer is a step-up or step-down.
AnswerTo determine the turns ratio if the turns ratio is unknown.
Can 10-2 yellow wire be used to run low voltage lights?
10-2 wire can be used to provide power to low-voltage lignts.
Does electrical resistance depend on temperature and bias voltage?
Electrical resistance depends on the temperature but not the biased voltage.
AnswerIt's resistivity that can be affected by temperature, which means that resistance is indirectly affected by temperature.
How much does a transformer cost?
Depending on their physical size, turns ratio, core material, design frequency of
operation, and power handling capability, transformers typically cost somewhere
between pennies and thousands of dollars.
What is a lockshield valve in a fire fighting system?
The lock shield valves are installed usually in the fire hose reel and the valve can be opened only by the key. and the key shall be kept with the maintenace team not in the valve. So the valve cannot be closed by the other people.
What is further education or training?
Further education or training means getting more knowledge on a particular field which you had been trained in. This is very useful for purposes of career development.
Whether alternating current or direct current is safer?
Well, voltage and current levels being identical, alternating current would be safer. It does not spend 100 percent of its time at peak voltage, therefore the average power in case of an electric shock is lower than that of direct current, which is 100 percent. This lesser average may allow some time to detach from the circuit and may not cause such catastrophe to the body.
Why you use sine wave for ac power supply why not triangle wave or square wave?
AC power comes from an electrical generator, which is a set of stationary coils (the stator) around a rotating magnetic field (the rotor). This configuration produces a sinewave output. We use a sine wave on the power grid because that's the way the electricity is generated, and it is a "natural" thing to do. It's a "pain" to have to convert it to another waveshape. There is also the fact that some nasty harmonics will appear on the power grid if we try to use triangular or square waves. Particularly with a square wave. The electrical loss will be higher, too. See the generator link below. Additionally, the sine wave is the the 'purest' waveform, being the root of all other period waveforms. See Fourier series link below.
Can a thyristor work as a circuit breaker?
A thyristor is primarily a very fast "switch-on" device and is not designed to be used as a "switch-off" device.
A circuit breaker is primarily a "switch-off" device which is used to automatically break the flow of current from a source to a load whenever the amount of current exceeds the rated current value of the breaker.
So, because a thyristor does not, all by itself, "open" a circuit, a thyristor cannot be used to work as a circuit breaker.
Notes
Current flow through a thyristor can only stop if - external to it - the current flowing through it gets reduced to below its minimum holding current or, of course, to zero, as would happen either:
i) if the load was disconnected from it by a separate circuit breaker that is wired into the circuit between the thyristor and the load;
or
ii) if the source was disconnected from it by a separate circuit breaker that is wired into the circuit between the supply and the thyristor.
Further notes
A thyristor is designed to close or "make" a circuit whenever:
a) an appropriate value of trigger voltage is put onto its gate
and then only if:
b) the current from the source to the load can flow through it in its "forward" direction.
One way of ensuring it automatically disconnects the load from the source is to use an alternating current supply and always "trigger" the thyristor so that it turns on during each positive-going part of each ac cycle.
Then, whenever the ac supply voltage returns to zero at the end of each positive half-cycle (after which it goes into the negative half-cycle) the thyristor will automatically break any further flow of current.
By using other electronic circuitry to determine exactly when the gate is triggered (earlier or later in each positive-going part of each cycle) the amount of power supplied to the load can be controlled very accurately.
That is why the main application for thyristors is to provide a precisely controlled way too use alternating currents to allow varying amounts of power to be supplied to electrical loads.
What is thermal power generation?
Thermal means "relating to heat." Geothermal (Earth's heat energy) energy is tapped by pumping water down deep bore holes under pressure, the water heats up and turns to steam. When it returns to the surface the steam is used to drive generators, whcih it turn produce electricity. Iceland, which has a lot of volcanic areas and hot springs, makes considerable use of geothermal energy.
What is the unit of electrical capacitance?
The unit of electrical capacitance is Farad (F) named after Michal Faraday. A farad is the charge in coulombs a capacitor will accept for the potential across it to change 1 volt. A coulomb is 1 ampere second.
Difference between transformer and induction motor?
1. Induction Motor has an air-gap but transformer has no air gap rather it is mutually link.
2. Induction Motor has high no-load current than transformer.
3. Induction Motor is a dynamic device.
4. Induction Motor has high power factor.
Which op amp is base of neural networks?
The generic op-amp would suffice for lab experiments. A number of summer amplifiers attached to a central amplifier attached to a comparator is what those at Robert Gordon University apparently use. The virtue of that design is that all those parts can be made from op-amps.
Although I have not tried it, a schmitt trigger, which can also be made from op-amps, can probably be used instead of a simple comparator - making analogue ternary (three-state) logic, in other words.
Cheers.
For details, see http://www.rgu.ac.uk/files/chapter10%20-%20implementing%20ANNs.pdf
Why is a resistor needed to discharge or charge a capacitor in an electric circuit?
A resistor may be used in series charging for current limiting, filtering, or as a signal isolater. Resistors across caps are to discharge them for your safety or equalize voltages across the caps in series filtering circuit.
Was the slant six motor originally a truck motor?
The SLANT 6 was introduced as the 6 cylinder engine in Chrysler corporation's 1960 automotive year model line. It was used in the compact 1960 Valiant, and the 1960 Dodge Dart. The Dart was a mid sized car. The engine replaced the venerable L head 6 that Chrysler had used since it introduction in 1930. The L head engine in fact continued to be the engine in the truck line for several additonal years. I believe the Slant 6 made it into the Dodge A 100 series of vans and cab forward Pickups, then into the standard pickup in 1963. The Plymouth Full size car line also had the /6 in 1960. Dodge introduced a compact similar to the Valiant know as the Lancer it also had a /6. The engines were available in two displacemets in 1960 the 170 for the Valiant and the 225 for the larger Dodge. The Lancer got both versions by customer selection. Later a 198 cubic inch was introduced as well. An Aluminum blocked version was experimented with but never made it to full production. Some were released unnanounced to the public in random production cars. The aluminum block had head to block sealing porblems which were never corrected satisfactorily for total introduction. So the simple answer is no, the /6 was introduced in cars before trucks. When it made it into trucks it was a very flexable and dependable powerplant in all it applications. It was also used for industrial and marine applications.
