1.Zero voltage regulation in a transformer occurs at :
(A)zero p.f. lead 
(B)unity p.f.
(C )leading p.f.
(D)lagging p.f.

2.A parallel plate capacitor has 15 p.F capacitance. If the linear dimensions of the plate are doubled and the distance between the plates are also doubled, then new value of capacitance would be :
(A)15uF
(B)30 uF
(C )60 uF
(D)7.5 u.F

3.Resistance of a 230 V 100 W bulb is R1 and that of a 230 V 75 W is R2. Then,
(A)R1= R2
(B)R1 > R2
(C )R1 < R2
(D)R1 - 2R2

4.The current in a series ....etc

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This is a new technique for the protection of transmission systems by using the global positioning system (GPS) and fault generated transients. In this scheme the relay contains a fault transient detection system together with a communication unit, which is connected to the power line through the high voltage coupling capacitors of the CVT.

Relays are installed at each bus bar in a transmission network. These detect the fault generated high frequency voltage transient signals and record the time instant corresponding to when the initial ....etc

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The recent growth of power circuit capacities has caused fault currents to increase. Since the protection of power systems from the fault currents is very important, it is needed to develop a fault current limiter.

A fault current limiter is required to assure (1) rapid reaction to fault currents, (2) how impedance in normal operation and (3) large impedance during fault conditions. A super conducting fault current limiter (SCFCL) can meet these requirements superconductors, because of their sharp transition from zero resistance at normal cu ....etc

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Lithium ion cells packaged in aluminium cans continue to be the highest performing cells in the market. Circuit protection for rechargeable lithium-based battery cells and packs in a critical design consideration.

overcurrent and overtemperature conduction that can result from accidental shorting or abusive/runaway charging can raise temperature high enough to damage components and cause substantial damage.

This paper presents the use of PPTC devices for short-circuit ....etc

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hi i am ali i want to know about seminar on impact of lightening on building and its remedial measure ....etc

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Introduction on over/under voltage protection of electrical appliances ....etc

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ABSTRACT:
This circuit protects refrigerators as well as other electrical appliances from over and under voltage. By the name itself we can say that if the input voltage is more or less than the required voltage then the electrical appliance is turned off nothing but it gets disconnected from its respective power supply.
This circuit uses an operational amplifier IC LM324 which is used as a comparator. Generally, the IC LM324 consists of four operational amplifiers, of which only two operational amplifi ....etc

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ABSTRACT



Because of high requirements in power, efficiency, installation space and weight, the design of electrical machines for hybrid electrical vehicles is a particular challenge. This seminar describes a comparative study allowing the selection of the most appropriate electric-propulsion system for a parallel hybrid electric vehicle (HEV). This seminar is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the four main electric propulsion systems, namely the d ....etc

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PROTECTION FOR YOUR ELECTRICAL APPLIANCES




Here is a very low-cost circuit to
save your electrically operated
appliances, such as TV, tape
recorder, refrigerator, and other
instruments during sudden tripping and
resumption of mains supply. Appliances
like refrigerators and air-conditioners are
more prone to damage due to such
conditions.

The simple circuit given here switches
off the mains supply to the
load as soon as the power
trips. The supply can ....etc

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This circuit protects refrigerators as well as other electrical appliances from over and under voltage. By the name itself we can say that if the input voltage is more or less than the required voltage then the electrical appliance is turned off nothing but it gets disconnected from its respective power supply.
This circuit uses an operational amplifier IC LM324 which is used as a comparator. Generally, the IC LM324 consists of four operational amplifiers, of which only two operational amplifiers are used. In this IC, we ha ....etc

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