0
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 is the difference between AC and AD?
AC is alternating current and AD is Anno Domini or after Christ.
What is the difference between spike and surge in electrical systems?
Surge suppressor, as name suggests suppresses and regulates the voltage and makes the power constant in a case of a spike or surge.
While a protector simply detects the surge and turns the unit off.
Suppressor is good for things like computers, where you don't want to keep turning on and off.
How do you know you have got an earth leakage?
there will be current that isn't carried by the current carrying conductors
What is the SI unit of electric charge?
That's the coulomb, equal to the quantity of charge moved
by a current of 1 ampere during an interval of 1 second.
Difference between fuse and mcb?
CB MCB
(i) Mechanism of CB is tripping relay. (i) Mechanism of MCB is tripping release
(ii) It is used in HV system. (ii) It is used in LV system.
(iii) Rupturing capacity is high . (iii) Rupturing capacity is low.
How would you measure power using one wattmeter in three phase?
There are several ways in which you can measure the power of a three-phase load, each of which requires the use of wattmeters, and the techniques vary according to whether the load is balanced or unbalanced. A common method is to use the 'two wattmeter method'. This cannot be explained here, but doing an internet search will provide a detailed explanation.
Another answer
Using a DVM from L1 to L2 or L3. Basically any combination. They should all be equal though, no matter which combination. If they are not, then there is a problem with one of the legs.
Comment
That is incorrect because you cannot use a DVM (digital voltmeter) to measure power.
The purpose of an oscillator is to produce repetitive sound that will compliment the music being played. They are relatively easy to set up and use. Oscillators will filter the sounds providing a wide range of music.
Which is better high resistance or low resistance resistor?
As little as possible, since the ammeter must be inserted in the circuit,
and the current it measures must flow through it.
What happens if two 120 volt loads are connected in series to a 240 volts service?
Burn correctly if they were ordinary light bulbs having the same power rating.
<><><>
However, if the loads were different, such as a 100 watt lamp and a 40 watt lamp - neither of them would produce the same amount of light.
If the loads were of very different types - say a 120 volt motor, which is a magnetic device, and a 120 volt computer, which is an electronic device - you can't say for sure how well they would each work when connected together in series across a 240 volt service without knowing a lot more facts about them.
What happens will always depend on the individual resistances and impedances of each load and how different they are.
<><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Why you use diode in the circuit?
It depends on the type of diode. Generally, diodes are use for converting AC supply to DC. That is particularly true of silicon rectifier diodes.
Germanium detector diodes are used in radios to detect the signal from the RF. Those same types of diodes are useful in logic circuits as well. They don't handle a lot of voltage or current, but they work fine with radio and computer signals.
A zener diode functions much like an ordinary diode until a breakdown voltage is reached, and then it will conduct the other direction, making it useful for voltage regulation. For instance if a zener is placed across some DC power leads after a fuse, then the unit may be protected from both excessive voltage and being hooked up backwards. If the device is connected to the DC source with the correct polarity, and if the voltage is not beyond the rated value, the diode will not conduct, and thus not blow the fuse.
A light-emitting diode is used primarily for producing light. Arrays of LEDs are used in displays, televisions and computer monitors. Even home and commercial lighting now uses LED technology.
What are common names for some primary discrete components used on circuit boards?
Resistors, capacitors, diodes
Why is the electric current you receive at your house is called alternating current?
The voltage and current are delivered in a sine wave that goes positive and then negative at 60 cycles per second. Google sine wave to see what a sine wave looks like.
How do you read resistor values?
Resistors have standard colors for identification of the resistance value. In order, the colors are: black, brown, red, orange, yellow, green, blue, violet, gray, and white. Reading resistors is a very simple procedure if you use the chart and formula below.
Hold the resistor with the gold or silver band to the right and read the resistor from the left to the right.
http://www.westfloridacomponents.com/reschart.html
What are 2 advantages for this particular control voltage?
With voltage control there is so much voltage drop due to resistor, that's the disadvantage
A swamping resistor is usually manufactured from the metal alloy manganin (trade name), or other alloy with similar resistance/temperature characteristics -i.e. practically zero temperature coefficient of resistance. In other words, its resistance will remain more-or-less constant over a wide range of temperature variation.
When were maglev trains first being used?
MagLev trains were first designed by a German man named Hermann Kemper. he was the first man to design and patent a MagLev train. The first MagLev train to be built and used was designed by Thyssen Henschel, another German, in the 1970's. The first passenger-carrying MagLev train was introduced in 1979 at the International Transportation Exposition in Hamburg, Germany. Thus began the MagLev train.
Circuit diagram of prepaid energy meter?
See the related link below.
It is build by using 8051 microcontroller, you can also get the source code from there.
What happens when a start capacitor fails?
An open circuit, by definition, has no continuity, therefore there is no current flow. A failed capacitor in an open circuit would have absolutely no effect.
Why does the current rise when the voltage drops?
It is not generally true that current increases when the voltage decreases. Ohms law for a simple resistor says that current is proportional to voltage.
However an electric motor supplying a constant mechanical load power will readjust to a lower supply voltage by drawing more current, although if the voltage is progressively reduced the motor would stall.
Switch-mode power supplies also tend to draw a constant power from the supply when the input voltage changes.
What are causes of change in voltage of alternators when loaded?
actully when load of alternator fluctuates it changes the torque at primovers which changes amps so terminal voltage of alternator changes.
Why DOL starter using to start motor?
Yes up to certain rating and application a motor can be started on DOL. Beyond a rating different methods need to be used to limit the starting current.
What would happen if you use one leg of a 220 circuit and it's neutral to power a 110 light?
it will lite . <P>
<P></P>Well, you sorta answered your own question, if you are talking residential wiring. The transformer in front of the house supplies 220V, center tapped, to your house. (we are talking the USA, right?) Center tapped means that the secondary of the transformer feeding your house is supplying 220, but there is a wire in the center of the secondary coil that has 110 between it and either end of the coil. If you look in your fusebox (breaker box in any newer home) you will see breakers on the left and on the right. The ones on the left side supply power from one end of the coil into your house and the center tap, and the ones on the other side supply power from the other end of the secondary and the center tap. 220 volts goes from either end of the secondary and doesn't bother with the center tap. I think the answer to the question is, you'll make light. be careful fooling with the cords, though.
What to do when there is voltage at neutral?
Quality of the earth pit needs to be checked and enhanced. Check the continuity of the earth bus/ conductor, check for improper joints in the earth bus / conductor and correct it. Earth resistance will reduce and the voltage difference between neutral and earth will also reduce.
Check also for the loose or floating neutral and correct it.
Why voltage induced when moving coil cuts flux?
The magnetic flux passing the coil changes by its rotation thus induced emf is produced and induced current flows
