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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
What voltage is need to make copper hot?
In order to get copper hot, you need a substantial powerdissipated by the copper.
Voltage alone is not the issue. You need to determine voltage across the copper, as well as current through the copper. With these two pieces of information, you can calculate the power in watts, or joules per second. Then you consider the thermal situation to decide if that power is going to create a temperature of a certain point.
What is total voltage in a series circuits?
In a series circuit the total voltage is the sum of the voltage drops across all the component in series. When the voltage drops across each the individual components are added up, they will equal the supply (or applied) voltage.
What must occur before the current flows through a circuit?
As current is the rate of flow of electric charges
- As I=Q/t
so,there must be free electrons for the flow of electric current in a circuit.Then when voltage is applied at the terminals of circuit the free electrons acquire an average velocity called as drift velocity in the opposite direction to that of electric field (-E).Now the free electrons modify there random motion and a steady current begin to flow in a circuit.
Why clipping happen for op-amp?
Clipping occurs in the voltage waveform when the input voltage, multiplied by the voltage gain of the op-amp circuit, exceeds the op-amp supply voltage as limited by the output network. The supply voltage and output network, limits the maximum voltage that can be achieved at the output. The op-amp behaves normally within its range of maximum voltage output, and then it is clipped when it reaches the maximum voltage of the circuit.
What are convection currents associated with electricity?
Convection current is current that is produced when a conductor induces a current in another conductor, and that other conductor is shorted.
An example would be a conductor going through a hole in a metal panel. The hole represents a one-turn transformer that is shorted. Convection current (or eddy current) represents a loss of power and it creates heat.
To avoid this, you either cut a slot in the panel to the hole, breaking the circuit, or you pass symmetrically opposed or balanced conductors through the same hole.
This is also why transformers are made with stacked plates, plates that are insulated from each other, and that individually do not create a circuit.
What is the Significance of back emf in dc motor?
Fig. (4.3)
ZN/60 A) is large and hence the motor will draw less armature current and vice-versa.
4.4 Significance of Back E.M.F.
The presence of back e.m.f. makes the d.c. motor a self-regulating machine i.e.,it makes the motor to draw as much armature current as is just sufficient todevelop the torque required by the load.Armature current,
aba
REVI
−=
(i) When the motor is running on no load, small torque is required toovercome the friction and windage losses. Therefore, the armaturecurrent I
a
is small and the back e.m.f. is nearly equal to the appliedvoltage.(ii) If the motor is suddenly loaded, the first effect is to cause the armature toslow down. Therefore, the speed at which the armature conductors movethrough the field is reduced and hence the back e.m.f. E
b
falls. Thedecreased back e.m.f. allows a larger current to flow through thearmature and larger current means increased driving torque. Thus, thedriving torque increases as the motor slows down. The motor will stopslowing down when the armature current is just sufficient to produce theincreased torque required by the load.(iii) If the load on the motor is decreased, the driving torque is momentarilyin excess of the requirement so that armature is accelerated. As thearmature speed increases, the back e.m.f. E
b
also increases and causesthe armature current I
a
to decrease. The motor will stop acceleratingwhen the armature current is just sufficient to produce the reduced torquerequired by the load.It follows, therefore, that back e.m.f. in a d.c. motor regulates the flow of armature current i.e., it automatically changes the armature current to meet theload requirement
Circuit diagram and working of potentiometer?
See the related link for a circuit diagram. The diagram pretty well explains how it works also. A potential is applied across the potentiometer. A movable contact moves across the voltage developed across the fixed portion and picks off the desired voltage.
How can you how can you detect wye from delta with neutral connections?
The star connection has three phase terminal leads and one neutral lead. In case of delta connection it has got three phase terminal leads. the star connection is generally represented by Mercedes symbol with neutral line drawn from the mid point. The delta is represented like a triangle symbol with noneutral line shown.
this type of substation are considered important because any sort of disturbance in these substation may lead to the failure of grid.this type of substation are used to transmit huge amount of power from one point to other point in the grid
AnswerA substation is a location where electricity transmission/distribution voltage-levels are changed and switching is carried out, as opposed to a power station, where electricity is generated. A substation, therefore, is a yard/building in which there are transformers, switchgear, busbar systems, and protection systems.
A grid substation is part of the electricity grid system -i.e. part of the transmission system. In the UK, this involves voltage levels of 400 kV, 275 kV, and 132 kV.
What is the use of capacitor before input of power supply AC?
They are used to offer a low impedence path to high frequency interference from switching sources such as fridges and thermostats. Also to curb radio frequency breakthrough.
How many volts are there in 63 amps?
Without knowing the resistance present or the power being consumed, it is not possible to determine how volts are present in a circuit with 63 amps. Ohm's Law: Voltage = Current times Resistance Volt: Joules per Coulomb
Ampere: Coulombs per Second
Watt: Joules per Second
When an alternating voltage is applied to purely resistive circuit what happens?
When an alternating voltage is applied to a purely resistive circuit, the resulting current is in phase with the voltage.
2 volts divided by 100 kOhms equals how many milliamps?
2 volts across 100 kOhms produces 0.02 milliamps (or 20 microamps) of current. Ohm's law: Voltage = Amperes * Ohms, so Amperes = Voltage / Ohms.
Write the construction of a moving coil galvanometer?
A moving coil Galvanometer consists of a coil PQRS which is wound over a non metalic frame having soft iron core in the middle. This Coil Is suspended in b/w a powerful magnet poles N-S with the help of Phosphor Bronze wire. Concave mirror is fixed on d suspending thread upside the coil through which deflection can b noted by Lamp and Scale arrangement. The lower end of the coil is connected by hair spring.
What happens when a bulb of 6volts used in an circuit?
depending at the kind and high at the voltage, or/and the high of the power
That's like asking how many meters in a liter.
Ampere and Volt are two DIFFERENT measurements.
Ampere is how much electricity you are using, while volts are how much pressure the electricity is under(Think water).
If you want to figure out how many amperes your appliance is using you could use this formula: P=UxI (Watt=Volt x Ampere) or U=RxI(Volt=Resistance x Ampere).
Can you have current without voltage?
Sure - an unconnected power supply of any kind - a battery is + at one end and - at the other.
What is the difference by v-75 PVC sheathed insulation and v-90 v-75 PVC sheathed insulation?
V90 is a higher temperature rating than V75. V90 cables can conduct more current without over heating/melting its insulation.
V110 is a higher rating than V90.
UniT transformer are step up transformer which is connected to generating house & step up voltage from 11/15kV votlage to 220/400kV voltage level as requirement or line design parameter.
It is just like transformer but connected to unit of the generating house that's why we called it unit transformers.
