Answer / karl

It is the circuit(type of) that affects whether current
will lead of lag voltage. An inductive circuit will cause
current to lag voltage due to magnetic fields that are
expanding or contracting in coils of wire. These fields
that expand and contract creates a back EMF that oppose the
current that is being applied to it and creating the
magnetic fields. The significance of this means that the
applied voltage will lead the the current and hence a power
factor now needs to be taken into account in this circuit.
A P.F. of 1 means that voltage is in phase. However with a
inductive circuit we will have a P.F. less that 1 and
lagging. e.g. maybe 0.75 lagging.

Answer / karl

I dont think the significance is that you will lose energy.
For example if I was to connect a capacitor in a AC
circuit, it would charge and then discharge back into the
supply. Therefore not using any real power. This would be
the same for a pure coil with its reactive energy. I think
the problem with a poor PF is that for a certain load you
may need to have a bigger transformer or generator. For
example a 1kW load with PF if 0.5 would need a xformer size
of 2kVA. If the PF was 1 you would need only a 1kVA
xtransofrmer even though you are still using the same power
and therefore energy.

Answer / puneet kumar

whenever ciruit contains inductive reactance(absence of
capacitive reactance) then current is lagging in nature
always in between 0 to 90 deg. depending on the impedence.
significance of lagging current means circuit has
inductive reactance surely which cause poor power factor
and this cause increase in imaginary loss turn to wastage
of energy due to poor p.f.

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