Advertisements
Advertisements
Question
Define the quality factor in an a.c. circuit. Why should the quality factor have high value in receiving circuits? Name the factors on which it depends.
Solution
The ratio`(omega_0L)/R`is called the quality factor or Q-factor.
`Q = (omega_0L)/R`
The quality factor has high value in receiving circuits in order to get a sharp gain for the desired channel frequency.
The quality factor depends on the values of the following:
-
Inductance
-
Resistance
-
Capacitance
APPEARS IN
RELATED QUESTIONS
An a.c. source of voltage V = V0 sin ωt is connected to a series combination of L, C, and R. Use the phasor diagram to obtain the expression for an impedance of a circuit and the phase angle between voltage and current. Find the condition when current will be in phase with the voltage. What is the circuit in this condition called?
When an AC source is connected to an ideal inductor show that the average power supplied by the source over a complete cycle is zero.
An A.C. generator generating an emf of ε = 300 sin (100 πt) V is connected to a series combination of 16μ F capacitor, 1 H inductor and 100 Ω resistor.
Calculate :
1) An impedance of the circuit at the given frequency.
2) Resonant frequency `f_0`
3)Power factor at the resonant frequency `f_0`.
The power factor of an a.c. circuit is 0.5. What is the phase difference between voltage and current in this circuit ?
A resistance is connected to an AC source. If a capacitor is included in the series circuit, will the average power absorbed by the resistance increase or decrease? If an inductor of small inductance is also included in the series circuit, will the average power absorbed increase or decrease further?
A coil has a resistance of 10 Ω and an inductance of 0.4 henry. It is connected to an AC source of 6.5 V, `30/pi Hz`. Find the average power consumed in the circuit.
An electric bulb is designed to consume 55 W when operated at 110 volts. It is connected to a 220 V, 50 Hz line through a choke coil in series. What should be the inductance of the coil for which the bulb gets correct voltage?
In previous questions 3 and 4, what is the net power absorbed by each circuit over a complete cycle. Explain your answer.
At a hydroelectric power plant, the water pressure head is at a height of 300 m and the water flow available is 100 m3 s–1. If the turbine generator efficiency is 60%, estimate the electric power available from the plant (g = 9.8 ms–2).
The power factor of an a.c circuit having resistance R and inductance L Connected in series to an a.c source of angular frequency co is.
