Q of a circuit - Revision history

Carlb: /* Admittance */

2009-06-05T02:22:11Z

Admittance

← Older revision		Revision as of 19:22, 4 June 2009
Line 28:		Line 28:
	For a given circuit element , the admittance is the reciprocal of the impedance.		For a given circuit element , the admittance is the reciprocal of the impedance.

	Admittance is most useful parallel AC circuit calculations where there are no series components. The equivalent admittance of a parallel circuit is the sum of the admittances of the components.		Admittance is most useful in parallel AC circuit calculations where there are no series components. The equivalent admittance of a parallel circuit is the sum of the admittances of the components.



	{{electronics}}		{{electronics}}

TimVK4YEH: added admittance

2009-06-04T02:18:31Z

added admittance

← Older revision		Revision as of 19:18, 3 June 2009
Line 23:		Line 23:

	<math>Q=\frac{P_{dissipated}}{P_{stored}}=\frac{I^2R}{I^2X}=\frac{R}{X}</math>		<math>Q=\frac{P_{dissipated}}{P_{stored}}=\frac{I^2R}{I^2X}=\frac{R}{X}</math>

			==Admittance==

			For a given circuit element , the admittance is the reciprocal of the impedance.

			Admittance is most useful parallel AC circuit calculations where there are no series components. The equivalent admittance of a parallel circuit is the sum of the admittances of the components.



	{{electronics}}		{{electronics}}

Carlb: /* How is '''Q''' calculated? */

2009-04-09T01:17:59Z

How is '''Q''' calculated?

← Older revision		Revision as of 18:17, 8 April 2009
Line 23:		Line 23:

	<math>Q=\frac{P_{dissipated}}{P_{stored}}=\frac{I^2R}{I^2X}=\frac{R}{X}</math>		<math>Q=\frac{P_{dissipated}}{P_{stored}}=\frac{I^2R}{I^2X}=\frac{R}{X}</math>


			{{electronics}}

TimVK4YEH: fixed links

2009-04-04T21:17:40Z

fixed links

← Older revision		Revision as of 14:17, 4 April 2009
Line 1:		Line 1:
	==What is '''Q'''==		==What is '''Q'''==

	The '''Q''' or ''Quality factor'' of a resonant circuit is the ratio of stored power to dissipated power in the [Reactance] and [Resistance] of the circuit.		The '''Q''' or ''Quality factor'' of a resonant circuit is the ratio of stored power to dissipated power in the [[Reactance]] and [[Resistance]] of the circuit.

	Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.		Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.

TimVK4YEH: /* What is '''Q''' */

2009-04-04T21:13:13Z

What is '''Q'''

← Older revision		Revision as of 14:13, 4 April 2009
Line 1:		Line 1:
	==What is '''Q'''==		==What is '''Q'''==

	The '''Q''' or''Quality factor'' of a resonant circuit is the ratio of stored power to dissipated power in the [Reactance] and [Resistance] of the circuit.		The '''Q''' or ''Quality factor'' of a resonant circuit is the ratio of stored power to dissipated power in the [Reactance] and [Resistance] of the circuit.

	Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.		Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.

TimVK4YEH: /* What is '''Q''' */

2009-04-04T21:12:49Z

What is '''Q'''

← Older revision		Revision as of 14:12, 4 April 2009
Line 1:		Line 1:
	==What is '''Q'''==		==What is '''Q'''==

	The '''Q''' or''Quality factor'' of a resonant circuit is the ~~ration~~ of stored power to dissipated power in the [Reactance] and [Resistance] of the circuit.		The '''Q''' or''Quality factor'' of a resonant circuit is the ratio of stored power to dissipated power in the [Reactance] and [Resistance] of the circuit.

	Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.		Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.

TimVK4YEH: added some detail and formulae

2009-04-04T21:12:11Z

added some detail and formulae

New page

==What is '''Q'''==

The '''Q''' or''Quality factor'' of a resonant circuit is the ration of stored power to dissipated power in the [Reactance] and [Resistance] of the circuit.

Generally speaking, a higher '''Q''' corresponds to a narrower bandwidth.

==How is '''Q''' calculated?==

Note that at resonance, a series circuit "appears" to be purely resistive (it behaves like a resistor). Below resonance it appears to be capacitive (it behaves like a capacitor), and above resonance it appears to be inductive (behaves like an inductor)

<math>Q=\frac{P_{stored}}{P_{dissipated}}=\frac{I^2X}{I^2R}=\frac{X}{R}</math> where:

* X = capacitive or inductive reactance at resonance
* R = series resistance
* P = Power
* I = Current

This formula is for all series resonant circuits and also works for parallel resonant circuits in which a small resistor is in series with the inductor.

If there is a large resistor in parallel with both the inductor and the capacitor, the formula becomes:

<math>Q=\frac{P_{dissipated}}{P_{stored}}=\frac{I^2R}{I^2X}=\frac{R}{X}</math>