0
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.
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
Why low power factor wattmeter is used for open circuit test of transformer?
For open circuit test of transformer, the secondary is open circuit and the circuit impedance is largely inductive due to the core impedance having high L as compared to R. hence the power factor is reduced, thus , we use low power factor wattmeters.
Does resonant frequency of RLC series circuit depends on Resistance?
No, the resonant frequency of a RLC series circuit is only dependant on L and C. R will be the impedance of the circuit at resonance.
How do you calculate the time constant for a simple series RL circuit?
The time constant of an RL series circuit is calculated using the formular: time constant=L/R
The resistor in an R-L series circuit has a voltage drop of 53V and the inductor has a voltage drop of 28V what is the applied voltage of the circuit?
The applied voltage is 53+28 = 81V.
Why LCR series circuit is called acceptor circuit?
Answer:A given combination of R,L and C in series allows the current to flow in a certain frequency range only.For this reason it is known as an acceptor circuit i.e.,it accepts some specific frequencies....
Under what condition will the power factor of a series R-L circuit approach unity?
When the Inductor's value equals Zero, then the Power Factor reaches 1. Conversly, when the Resistance equals 0, the Power Factor becomes Zero. The Power Factor for a Series R-L Circuit is equal to R / sqrt (R^2 + (w*L)^2 )
What is the power factor on a circuit in resonance?
You are presumably referring to an 'R-L-C' circuit. At resonance, the load current is in phase with the supply voltage and, so, the power factor is unity.
Why low power factor wattmeter is used for open circuit test of transformer?
For open circuit test of transformer, the secondary is open circuit and the circuit impedance is largely inductive due to the core impedance having high L as compared to R. hence the power factor is reduced, thus , we use low power factor wattmeters.
An R-L series circuit has a power factor of 86 percent How many degrees are the voltage and current out of phase with each other?
If you have access to a calculator: Click cos-1 then .86 to get an answer of 30.6834
Why you use three phase supply in experiment of power factor of RL series circuit?
You don't necessarily. For a straightforward series (or parallel) R-L load, you will only require a single-phase supply. However, if you had three R-L loads, connected in delta or star (wye), then you would require a three-phase supply.
Does resonant frequency of RLC series circuit depends on Resistance?
No, the resonant frequency of a RLC series circuit is only dependant on L and C. R will be the impedance of the circuit at resonance.
How do you calculate the time constant for a simple series RL circuit?
The time constant of an RL series circuit is calculated using the formular: time constant=L/R
Resonance in an L-C-R AC Series circuit experiment?
At resonant frequency, current in the circuit is maximum.Impedence is minimum.
What is power factor of an R-L series circuit?
Power factor is real power divided by total power. Power factor can be written as: pf = R / sqrt(R^2 + X^2), where X is the reactive resistance of the active elements (in this case, L): pf = R / sqrt (R^2 + (wL)^2) w = frequency in radians of the AC frequency for which the power factor is to be calculated.
Does the current reach its maximum peak value at the same instant time in as does the voltage?
Yes if the power factor is unity.Additional AnswerOnly if the load is purely resistive. For a resistive-inductive (R-L) load, the current will reach its maximum value after the voltage reaches its maximum value, and we say the current is 'lagging the voltage'. For a resistive-capacitive (R-C) load, the current will reach its maximum value before the voltage reaches its maximum value, and we say the current is 'leading the voltage'.The angle of lag or lead is called the circuit's 'phase angle' and the cosine of that angle is termed the circuit's 'power factor'. So, for a purely-resistive circuit, the phase angle is zero and the power factor is 1 ('unit'). For R-L circuits, the power factor is less than 1, and is described as 'lagging'. For R-C circuits, the power factor is also less than 1, and is described as 'leading'.
What is the Internal circuit diagram of crystal oscillator?
Ans. A series L R C in parallel with C' .
What is the unit of quality factor of RLC series circuit?
The selectivity or sharpness of series resonant circuit is measured by quality factor or Q factor.It is defined as the ratio of the voltage across the coil or capcitor to the applied voltage.In other words it refers to the sharpness of tuning at resonance. Q = voltage across L or C ( in volts) / applied voltage ( in volts ) Q = 1/ R * ( L/C)^ 0.5 Q is just a mere number having values between 10 to 100 for normal frequencies.So it has no unit. Circuit with high Q values would respond to a very narrow frequency range and vice versa.Thus a circuit with high Q value is sharply tuned while a circuit with low Q value has a flat resonance.Q factor can be increased by having a coil of large inductance but of small ohmic resistance.
