ratio between true power and apparent power is called the power factor for a circuit Power factor =true power/apparent power also we conclude PF=power dissipated / actual power in pure resistive circuit if total resistance is made zero power factor will be zero
these two types of circuit loads are the purely capacitive loads and purely inductive loadsAnother AnswerApparent power will be larger than true, or active, power in ANY circuit, other than a purely-resistive circuit or an R-L-C circuit at resonance.
Although we can't necessarily see electricity, we can measure it by its effects. An ampere, or amp, represents the amount of current in a circuit. Voltage is defined scientifically as the circuit's "potential difference," and can be seen as the amount of "pressure" that drives electricity in a circuit. Watts are a measure of the use of electrical power, and one watt is equal to one volt multiplied by one amp.Additional AnswerThe watt is used to measure an AC circuit's true power, whereas a volt ampere is used to measure the circuit's apparent power.Apparent power is the product of current and voltage, whereas true power is the product of current, voltage, and power factor.The true power of an AC circuit is measured using a wattmeter, whereas the apparent power is the product of current and voltage.
Power factor is:the ratio of true power to apparent powerthe ratio of resistance to impedancethe ratio of the voltage across a circuit's resistive component to the supply voltagethe cosine of the phase angleetc.
The resistor is the only component to develop true power in an ac circuit. The inductor and capacitors absorb energy on one half cycle and return it to the supply on the next. The resistive part of the inductor (wire coil if low frequency type) will develop true power due to its value of resistance ie it will get warm.
'Reactive power', measured in reactive volt amperes (var), describes the rate at which energy is supplied to, and stored within, a circuit's magnetic and/or electric field(s) and, then, returned to the supply, during every half cycle of alternating current.Contrast this with 'true power', measured in watts(W), which describes the rate at which energy is permanently expended overcoming a circuit's resistance or through doing work (e.g. by an electric motor delivering energy to its mechanical load).Reactive power is sometimes described as 'wasted power'; this is a complete misconception, because reactive power is essential, as it is required to establish and maintain a circuit's magnetic and/or electric fields.The combination (vectorial sum) of true power and reactive power, is called 'apparent power', measured in volt amperes (V.A).The true power of a circuit is measured using a wattmeter, while apparent power is simply the product of the supply voltage and the load current.
Power factor in any circuit is the ratio of the load's true power to its apparent power. It's also the cosine of the phase angle. In L-R circuits, it's described as a 'lagging power factor', because the load current lags the supply voltage.
Inductors are considered to be a load for reactive power, meaning that they will draw reactive power from the system. Capacitors are considered to be sourced of reactive power, they feed reactive power into the system. If you have a circuit that is at unity (balanced with inductors and capacitors) no reactive power will be drawn from the source. You will have unity power factor. If your circuit is more inductive than capacitive it will be drawing reactive power from the source. The opposite is also true for capacitors.
By definition, power factor is the cosine of the angle by which the load current lags or leads the supply voltage in an AC circuit. It is also the ratio of true power to apparent power. A lagging power factor occurs in an resistive-inductive circuit, where the load current lags the supply voltage. A leading power factor occurs in an resistive-capacitive circuit, where the load current leads the supply voltage
'Reactive Power', which is expressed in reactive volt amperes, describes the rate at which energy is alternately stored (in a circuit's electric or magnetic field) and returned to the a.c. supply when the field collapses. It differs from true power, expressed in watts, because true power describes the rate at which energy is permanently lost by heat transfer due to the resistive component of the circuit.Reactive power doesn't 'have an use', per se, it's merely a way of quantifying the movement of energy in the reactive component of an a.c. circuit.The vector sum of a circuit's reactive power and its true power is called the apparent power of the circuit, expressed in volt amperes.