Answer / amey

the equestion of capasitor=(q=cv)
or q=c*Vm sinwt.
now current is the rate of flow of charge.
therefore,dq/dt=c*Vm*w coswt.
i=c*Vm*w coswt.
Im sinwt=Vm/(1/wc)sin(wt-90)...........(1)
now from this equestion curent(Im) leads voltage(Vm) by
angle 90 degree.

Answer / prasad

It must be first understood here that the capacitor
current leads the voltage across capacitor & not the supply
voltage.
Whenever A.C. voltage is applied across the capacitor,
initially free electrons start conducting current offering
zero resistance & thus no voltage across the capacitor. As
the capacitor plates start getting charged (Polarity opp to
supply) it starts offering resistance to current & voltage
starts to appear across capacitor.

Answer / pancham

Pure capacitive circuit: capacitor voltage lags capacitor
current by 90o
pure capacitive circuit waveforms. plz plot the wave form
b/w current &voltage.

Remember, the current through a capacitor is a reaction
against the change in voltage across it. Therefore, the
instantaneous current is zero whenever the instantaneous
voltage is at a peak (zero change, or level slope, on the
voltage sine wave), and the instantaneous current is at a
peak wherever the instantaneous voltage is at maximum
change (the points of steepest slope on the voltage wave,
where it crosses the zero line). This results in a voltage
wave that is -90o out of phase with the current wave.
Looking at the graph, the current wave seems to have
a “head start” on the voltage wave; the current “leads” the
voltage, and the voltage “lags” behind the current.

Answer / tarun aggarwal

if we say voltage at any instant is at time t

v = Vsin(wt + @ )

and we know in case of capictor
Ic = C * dv/dt

Ic = C*( Vcos(wt + @) )*w

Ic =c*w *(sint(wt + @ + 90) )
this clearly show that current leads voltage

also in case of capacitor .it start charging from zero to
full voltage while current is there to charge it which also
is physical interpretation of leading curent

Answer / deepakindi1

current through capacitor=

ic= c dvc/dt

ie current through capacitor is a function of rate of
change of voltage applied across it, as applied voltage is
sinusoidal sine wave ,if u take a slope at zero croosing of
wave form rate of change of the voltage is maximum so is
the current at zero croosing of wave form is maximum. that
ic reaches its maximum before applied voltage that y
current through capacitor leads voltage

Answer / balaji

capacitor is nothing but two metallic plates seperated by a
dielectric medium..if we give supply to a capacitor the
flow of oppositely charged particles begin results in the
flow of current resembles like short circuit.voltage in a
short circuit is zero...once the metal plates get charged
no particles will move and it behaves like a open circuit
having supply voltage across it and the current becomes
zero.

Answer / kumar.shyam1

capacitor it stores the energy in the form of static field
and when no magnetic field no change of flux
so inductive part when it is a pure capacitor
from this we can say current is dominating

y it generates static field because of dielectric medium

Answer / 5hj4rbv5v3

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Answer / a.balakrishnan

capacitor are always lead from voltage.Because if we give
the supply to the capacitor,at first the capacitor do
discharge,then charge.We can invent the angle of leading
from wave forms.Its leads angle may choosing of capacitor.

When we have earthing mesh or underground earthing network in industrial plants, weather we have NT-S or NT-C-S kind of earthing system, so eventually weather we must use 4 or 5 wire in 400 volt level (For example 3×150+70 mm2 or 5×150 mm2) in this connection I would like to know exactly the paragraph of IEC or IEEE number

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