SIRKOTS
Resistance
The selectivity of a series resonance circuit can be controlled by adjusting the value of the
Quality Factor
The sharpness of the peak of a resonance curve described by a dimensionless quantity is known as the
Quality Factor
This is an indication of how much energy is placed in storage (continual transfer from one reactive element to the other) compared to that dissipated.
Becomes capacitive
What will happen to a parallel AC circuit if its line or operating frequency is more than the resonant frequency?
The rms voltage is always greater than the average voltage.
When comparing rms voltages and average voltages, which of the following statement is true, assuming sine waves?
Pass or reject selected frequency ranges in radio and television communications.
Where do resonant circuits are mostly used in practical applications?
The greater the value of Q, the less bandwidth a resonant circuit will have
Which of the following statements is true?
millman's theorem
for AC circuits states that if 'n' number of voltage sources V1, V2, and so on having internal impedances Z1, Z2 and so on are connected in parallel across the load Zl then this arrangement may be replaced by a single voltage source Veq in series with equivalent impedance Zeq.
maximum power transfer theorem
for AC circuits states that when a load is connected to a circuit, maximum power is transferred to the load when the load impedance is the complex conjugate of the circuits' output impedance.
hay's bridge
modified version of maxwell's bridge. used to measure high value of inductance.
wein's bridge
primarily known as frequency determining bridge and find its application harmonic distortion analyzer, audio and HF oscillators etc. used for measuring the frequency of a source. ADVANTAGES: this may be used for measurement of capacitors also. DISADVANTAGES: due to frequency sensitivity, the wein bridge may be difficult to balance unless the waveform of applied voltage is of sinusoidal.
Thevenin's and Norton's Theorem
the circuit is divided into two ports, A and B with two joining wires a and b.
maxwell's bridge
used for accurate measurement of inductance and resistance of a coil in terms of a standard capacitor Cs. two arms consists of a single resistor, one arm consist of RL series combination and one arm consist of RC parallel combination. ADVANTAGES: both values of Rx and Lx are independent to the value of frequency, hence, easy to balance. DISADVANTAGES: perfect balance can never be achieve due to stay capacitors and presence of harmonics in AC source. requires a variable standard capacitor which may be expensive if calibrated to high degree of accuracy.
de-sauty bridge
used to determine the capacity of an unknown capacitor Cx in terms of a standard known capacitor Cs. ADVANTAGES: simplicity to obtain balance DISADVANTAGES: perfect balance can only be obtained, only if both are free from dielectric losses i.e. air-capacitors are used.
bridge circuit
used to measure inductance or capacitance in the same way that a wheatstone bridge can be used to measure the resistance.
Will remain the same.
A certain resonant circuit has a resonant frequency. What would be its value if the value of inductance is doubled and the capacitance is halved?
Resistive
A given AC circuit is said to have a voltage and current that are in-phase with each other. What type of circuit is it?
Resistive
A parallel circuit at resonance would mean that the circuit is
Current leads the voltage by 45deg
A resistive and a capacitive load of equal magnitude is connected in series, determine the phase difference between the voltage and the current.
Selectivity
The __________ of a circuit is the measure of its ability to reject any frequencies either side of these points.
Reactive
If the current and voltage in an AC circuit has a phase difference, it would mean the load is
When the voltage and current are in-phase
In general, when can we say that a parallel circuit is at resonance?
The higher is the voltage
In transformer windings, the greater number of turns
