Electrical Engineering

advantages is:1) we are able to analyse relationship between current and voltage.2)able to give the resistance applied in circuit.there is only one limitations that is it can change its value if the circuit is left on for long time.thankyou:).

'Force' isn't measured in volts. Potential and potential difference are measured in volts.

the highest transmission volatage in India is 765kV ac. The highest voltage in the case of DC transmission is +/- 600 kV.

S = Apparent Power

P = Real Power [Negative for supplied power, positive for absorbed power]

Q = Reactive Power [Positive for lagging or inductive loads, negative for leading or capactive loads]

Fp = Power Factor [Specified as lagging or leading for inductive or capacitive loads respectively]

V = Voltage

I = Current

* = (Conjugate)

< = 'At an angle of'

For DC cases:

|P| = P = V x I = V^2 / R = I^2 x R

For AC cases:

S = V x I* = |S| < arccos(Fp)

|S| = |V| x |I|

|P| = |S| x Fp

|Q| = sqrt(|S|^2 - |P|^2)

If the magnetic field applied to a magnetic material is increased and then decreased back to its original value, the magnetic field inside the material does not return to its original value. The internal field 'lags' behind the external field. This behaviour results in a loss of energy, called the hysteresis loss, when a sample is repeatedly magnetized and demagnetized. The materials used in transformer cores and electromagnets are chosen to have a low hysteresis loss. Similar behaviour is seen in some materials when varying electric fields are applied (electric hysteresis). Elastic hysteresis occurs when a varying force repeatedly deforms an elastic material. The deformation produced does not completely disappear when the force is removed, and this results in energy loss on repeated deformations.

35 to 70

It depends on the mix of concrete you are using. A basic 1-2-3 mix is 5 1/2 cubic feet of portland cement (a wheelbarrow, depending on its size, holds 1/2 to 1 cubic feet), 11 cubic feet of sand, and 16 1/2 cubic feet of stone (called aggregate) from 1/2 to 1 inch in size each. To this is added about 12-15 gallons of water.(1 1/2 to 2 cu.ft.). This will make just a little less than 1 cubic meter of concrete.

A weaker mix for basic work not needing structural strength a 1-2-3 mix of 1 part stone, 2 parts cement and 3 parts sand can be used, this would require a bit less than 1 part water.

A stronger mix of 1 part cement, 1 1/2 parts sand and 3 parts stone with about 1/2 part water is good for heavy duty concrete work. Stone will increase the strength of concrete and sand will weaken it. Using too much or too little water in the mix will weaken it as well. Additionally, concrete with too much water or too little cement tends to shrink and crack as it sets. The amount of water to use is mainly dependent on the cement in the mix. There should be at least half as much cement as sand in any mixture. The amount of stone to use should be between 1/4 and 3/4 of the total mixture. Grouts and mortars use no stone and may add limestone as an additional binder. These should not be used for structural concrete, but can be used for foundation pointing, bolt anchoring or mortaring brickwork.

Batteries in series makes the voltage additive. If the bulb is only rated at a specific voltage and you double the voltage the bulb will glow brighter but its life span will be shortened. Batteries in parallel will keep the voltage at the same level as a single battery but the endurance drain of the batteries will be doubled. Example, if a battery is drained of power, with a bulb being left on continuously, in one hour then two batteries in parallel would allow the bulb to glow for two hours before the batteries were drained of power.

The application of engineering knowledge to the development of medical products. The engineering disciplines involved range from the traditional engineering fields to software and genetic engineering. The field is broken up into a number of specialty areas as varied as the biological and engineering fields from which they spring.

Single bus is used in smaller, less important substations. A fault on the bus requires tripping of all lines into the bus. When higher redundancy is necessary, ring and breaker and 1/2 schemes are used. These are the three most common.

rms. dat means Vp-p will be 325V.

You reduce voltage in a DC circuit with a resistor. If the power demands are high, however, you may need a switching voltage regulator.

Voltage = resistance X current abbreviated,
V = C * R


If you halve the voltage of the current, then the other side of the equation must also be halved; therefore, you get:


(1/2)V=(1/2)(C*R)


which is the same as:


(1/2)V=(1/2)(C)(R)


which means that either the current or the resistance must be halved as well, and because the resistance stays the same, then the current is halved.

A transformer makes and collapses a magnetic Field inside 60 times a second for home power in North America, 50 times a second in Europe.

The building and collapsing of a magnetic field "Induces" a voltage in another transformer winding.

DC current only creates a stable magnetic field and this will not create or induce voltage in the other winding.

Normally covered in grade 5 science where I live.

A relay can be seen as a messenger. In electricity, a relay is a electromagnetic switch which closes or opens its contacts if its coil is energized by electricity. It can only handle small voltage or current typically 24vdc or 240vac.

The output of motors are only measured in horsepower in North America. Practically everywhere else, the output is measured in watts. The horsepower and the watt both measure exactly the same thing: power. The horsepower is simply the Imperial unit, whereas the watt is the SI unit. They are interchangeable.

1. Provides a high data rate.

2. cost of purchsing towers for transmission is pretty low.

3. small antennas are required.

4. No cables needed

5. Multiple channels available

6. Wide bandwidth

Every line has an upper limit and a lower limit on the frequency of signals it can carry. This limited range is called the bandwidth. The signals ranging within the upper limit & lower limit are called bandwidth signals.

Loads receive current independently of each other.

Typical applications; "the motor will have a limited amount of torque, lesser in value than what is needed for normal operation. Thus, is real world workings the unit will overload, stop, not work, trip OL.

The magnetization current imposes an upper limit on the voltage applied to a transformer core due to the ability of the respective spark gap to extinguish. If too much current supply is available the spark gap becomes overheated. This makes it unable to "switch-off" when the high or elevated supply current is flowing through it.

600 volts is five times the 120 volt primary, so the secondary winding must have 750 turns, which is five times as many turns as the 150 turns of the primary winding.

For an 'ideal' transformer operating at full load, the answer is yes. But, 'real' transformers are a little less than 100% efficient so, in practice, the input power will slightly exceed the output power. In most circumstances, for the purpose of calculating primary and secondary currents, we can assume 100% efficiency.

An electric generator converts mechanical energy to electric energy while a motor converts electric energy to mechanical. A generator can actually act as a motor if it losses whatever is making it spin (called "motoring"), which is usually a very bad thing. Motors may be used as generators as well, depending on their design.