Parallel resonance circuits, also known as tank circuits, consist of an inductor (L) and a capacitor (C) connected in parallel to an alternating current (AC) source. In these circuits, resonance occurs when the inductive reactance (XL) and capacitive reactance (XC) are equal, resulting in a condition where the total impedance of the circuit is at its maximum and purely resistive. This leads to a significant increase in current at the resonant frequency, while the circuit effectively minimizes the current drawn from the source. Parallel resonance circuits are widely used in applications such as radio frequency tuning, filters, and oscillators, as they can selectively amplify or attenuate specific frequencies, making them essential in communication and signal processing technologies.
What is a parallel resonance circuit?
A parallel resonance circuit is an electrical circuit that consists of an inductor and a capacitor connected in parallel, where resonance occurs when the inductive and capacitive reactances are equal, resulting in maximum impedance.
What condition must be met for resonance to occur in a parallel resonance circuit?
Resonance occurs when the inductive reactance (XL) equals the capacitive reactance (XC), which can be expressed as XL = XC.
How does the impedance of a parallel resonance circuit behave at resonance?
At resonance, the impedance of the circuit is at its maximum and is purely resistive, meaning that the circuit draws minimal current from the source.
What happens to the current in a parallel resonance circuit at resonance?
At resonance, the current through the inductor and capacitor can be significantly larger than the current drawn from the source, as the two branch currents can resonate and amplify each other.
How does the bandwidth of a parallel resonance circuit relate to its Q factor?
The bandwidth of a parallel resonance circuit is inversely proportional to the Q factor; a higher Q results in a narrower bandwidth, while a lower Q leads to a wider bandwidth.
What is the primary characteristic of a parallel resonance circuit at resonance?
a) Maximum current
b) Minimum impedance
c) Maximum impedance
d) Zero current
Answer: c) Maximum impedance
In a parallel resonance circuit, resonance occurs when which of the following conditions is met?
a) XL > XC
b) XL < XC
c) XL = XC
d) R = 0
Answer: c) XL = XC
What happens to the current through the inductor and capacitor at resonance in a parallel resonance circuit?
a) They are equal
b) They are zero
c) They are out of phase
d) They can be significantly larger than the source current
Answer: d) They can be significantly larger than the source current
What does a higher quality factor (Q) indicate in a parallel resonance circuit?
a) Wider bandwidth
b) Lower selectivity
c) Sharper resonance peak
d) Higher resistance
Answer: c) Sharper resonance peak
Which of the following components is NOT typically found in a parallel resonance circuit?
a) Inductor
b) Capacitor
c) Resistor
d) Transformer
Answer: d) Transformer