The resonance effect occurs when inductive and capacitive reactances are equal in absolute value. The frequency at which this equality holds for the particular circuit is called the resonant frequency. The resonant frequency of the LC circuit is
\omega = \sqrt{1 \over LC}
where L is the inductance in henries, and C is the capacitance in farads. The angular frequency \omega\, has units of radians per second.
The equivalent frequency in units of hertz is
f = { \omega \over 2 \pi } = {1 \over {2 \pi \sqrt{LC}}}.
LC circuits are often used as filters; the L/C ratio is one of the factors that determines their "Q" and so selectivity. For a series resonant circuit with a given resistance, the higher the inductance and the lower the capacitance, the narrower the filter bandwidth. For a parallel resonant circuit the opposite applies. Positive feedback around the tuned circuit ("regeneration") can also increase selectivity (see Q multiplier and Regenerative circuit).
Stagger tuning can provide an acceptably wide audio bandwidth, yet good selectivity.
\omega = \sqrt{1 \over LC}
where L is the inductance in henries, and C is the capacitance in farads. The angular frequency \omega\, has units of radians per second.
The equivalent frequency in units of hertz is
f = { \omega \over 2 \pi } = {1 \over {2 \pi \sqrt{LC}}}.
LC circuits are often used as filters; the L/C ratio is one of the factors that determines their "Q" and so selectivity. For a series resonant circuit with a given resistance, the higher the inductance and the lower the capacitance, the narrower the filter bandwidth. For a parallel resonant circuit the opposite applies. Positive feedback around the tuned circuit ("regeneration") can also increase selectivity (see Q multiplier and Regenerative circuit).
Stagger tuning can provide an acceptably wide audio bandwidth, yet good selectivity.
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