A wattmeter reads the true power of a load, regardless of its power factor.
Power factor is the ratio of true versus apparent power. For example, a power factor of 1 means that one watt of measured power is one watt of real power, while a power factor of 0.5 means that one watt of measured power is two watts of real power.To measure power factor, measure voltage, current, and the phase angle of current related to voltage. Phase angle is between 0 and 360 degrees, 360 degrees being one line cycle.A power factor of 1 means that the phase angle is 0 degrees.A power factor of 0.707, assuming that voltage and current are measured on the same scale, means that the phase angle is 45 degrees. It would be +45 degrees for a capacitive load and -45 degrees for an inductive load. You can use trigonometry, sines and cosines, to figure this out, or you can use the pythagorean theorem to figure this out - its just a right triangle where the angle is the phase angle.By the way, a power factor of -1 means the load is actually a generator, and a power factor of 0 means the load is a pure capacitive or inductive load with a phase angle of +90 or -90 degrees.Power factor is a concern because watt-meters measure apparent power. If the power factor is too low, it will seem that the energy used to lower than reality. The problem is, even in the worst case of + or - 90 degrees, energy is still required to move the current back and forth in the circuit, and that energy must come from the power supply. That's why we talk volts-amps (VA), volts-amps-reactive (VAR), and watts (W) in AC circuits, and none of them are the same thing.
because of high resistance in the load.
at lower power factor current drawn by load is high and at higher pf the current drawn is less...
Low power factor means higher than necessary load currents. These require unnecessary expenditure on the amount of copper in supply equipment such as cables, transformers, and switchgear. Higher than necessary load currents also mean greater voltage drops and poorer voltage regulation.
A load with a low power factor draws more load current than necessary, so the supply conductors need to have a greater cross-sectional area than would otherwise be necessary.
The load (in this case, your led lighting) determines its own power factor. While you can improve the power factor (move it towards unity) at the terminals, you are not actually changing the power factor of the load.
In an AC system the power is often less than the volts times the amps. The full formula is watts = volts times amps times power-factor. Some bulbs have a power-factor as low as 0.5.
There is no such thing as a 'low power-factor' wattmeter. A wattmeter always reads true power, regardless of the load's power factor.
Yes, theoretically you can power up a laptop with a 65 watt power adapter using a 300 watt DC to AC inverter, as the laptop will only draw the power it needs (65 watts). However, it's important to ensure that the inverter has low voltage and overload protection to prevent any damage to the laptop or the inverter itself during operation.
Power factor is determined by the nature (resistive, inductive, capacitive) of a load, not whether it is a low load or a high load.
It isn't! A transformer operating at no load has a very low power factor.
When looking at power factor, it is the ratio of watts (true power) to VA. The power factor is how we measure power systems. A person with a low power factor like .26 will have a higher electricity bill.
Between 2 standard IR devices it is 1 meter. Between 2 low power IR devices it is 0.3 meter Between a standard and a low power IR device it is 0.2 meter
The package size roughly equates to wattage- the amount of power a resistor can safety dissipate without damage. Use your basic ohms law to figure out how much power will be dissipated by the resistor, and use the next largest size. A good safety factor is 2, so if you calculate the power is 1/4 watt, use a 1/2 watt resistor. One other factor is duty cycle. A component with a low duty cycle would need less of a safety factor, or perhaps could be sized according to the AVERAGE power in the resistor.
Yes, you can run a 500 watt amplifier at low volume on a 140 watt AC converter. The power consumption of the amplifier will depend on the volume level it is set to. As long as the amplifier is not drawing more power than what the converter can supply, you should be able to use them together safely. Keep an eye on the power indicator on the converter to ensure it's not being overloaded.
inductive/lagging load
Power factor is the ratio of true versus apparent power. For example, a power factor of 1 means that one watt of measured power is one watt of real power, while a power factor of 0.5 means that one watt of measured power is two watts of real power.To measure power factor, measure voltage, current, and the phase angle of current related to voltage. Phase angle is between 0 and 360 degrees, 360 degrees being one line cycle.A power factor of 1 means that the phase angle is 0 degrees.A power factor of 0.707, assuming that voltage and current are measured on the same scale, means that the phase angle is 45 degrees. It would be +45 degrees for a capacitive load and -45 degrees for an inductive load. You can use trigonometry, sines and cosines, to figure this out, or you can use the pythagorean theorem to figure this out - its just a right triangle where the angle is the phase angle.By the way, a power factor of -1 means the load is actually a generator, and a power factor of 0 means the load is a pure capacitive or inductive load with a phase angle of +90 or -90 degrees.Power factor is a concern because watt-meters measure apparent power. If the power factor is too low, it will seem that the energy used to lower than reality. The problem is, even in the worst case of + or - 90 degrees, energy is still required to move the current back and forth in the circuit, and that energy must come from the power supply. That's why we talk volts-amps (VA), volts-amps-reactive (VAR), and watts (W) in AC circuits, and none of them are the same thing.