i have an assignment for home and have a question and i don't know where to find the answer i have search alot. Can someone pls help me. the question is "Explain the difference between the q-factor of a circuit and the q-factor of a coil?" thanks for your help
question about q-factor
- Thread starter mrozmt
- Start date
What type of circuit? Q-factor is general refers to ratio of energy stored to energy dissipated at a frequency. For an inductor this is usually omega*L/R and is a measure of how "ideal" (lossless) it is. For a circuit the formula depends on the particular circuit but it still has the form of omega*energy stored/energy lost
Hello,
Here are two pages from the wiki.
1 st : about inductors, they have a q-factor for powerloss.
http://en.wikipedia.org/wiki/Inductor
2 nd : about rlc circuits, here the q-factor has to do with the bandwith of a rlc-circuit.
http://en.wikipedia.org/wiki/RLC_circuit
Greetings,
Bertus
Here are two pages from the wiki.
1 st : about inductors, they have a q-factor for powerloss.
http://en.wikipedia.org/wiki/Inductor
2 nd : about rlc circuits, here the q-factor has to do with the bandwith of a rlc-circuit.
http://en.wikipedia.org/wiki/RLC_circuit
Greetings,
Bertus
silvrstring
- Joined Mar 27, 2008
- 159
Hello mrozmt.
The Q factor of the circuit is the ratio of reactive power to avrerage power.
For a series filter at resonance, this would be Q=X(L)/R. For a parallel circuit, it is Q=R/X(L).
It is important because it determines the selectivity of your filter. The bandwidth of your filter will be f/Q, so the higher your Q factor, the smaller your bandwidth.
Sometimes, an inductor will have its own Q included in the schematic. You will need to include it in your calculations to obtain Q of the circuit.
Q of the inductor = X(L) / R of the inductor.
Example: if Q(coil) = 50, and X(L)=100, then R(coil) = 2ohms, and R(total) = R+R(coil). This in turn effects Z(total) which effects your I result (because I=E/Z) and your V(L) and V(c) result, therefore your average power, and reactive power for the inductor.
Finally, you can find Qfactor of the circuit by Qseries=Q(L)/P. (Q(L) here is the reactive power of the inductor, not the Qfactor of the inductor).
Hope this helps.
The Q factor of the circuit is the ratio of reactive power to avrerage power.
For a series filter at resonance, this would be Q=X(L)/R. For a parallel circuit, it is Q=R/X(L).
It is important because it determines the selectivity of your filter. The bandwidth of your filter will be f/Q, so the higher your Q factor, the smaller your bandwidth.
Sometimes, an inductor will have its own Q included in the schematic. You will need to include it in your calculations to obtain Q of the circuit.
Q of the inductor = X(L) / R of the inductor.
Example: if Q(coil) = 50, and X(L)=100, then R(coil) = 2ohms, and R(total) = R+R(coil). This in turn effects Z(total) which effects your I result (because I=E/Z) and your V(L) and V(c) result, therefore your average power, and reactive power for the inductor.
Finally, you can find Qfactor of the circuit by Qseries=Q(L)/P. (Q(L) here is the reactive power of the inductor, not the Qfactor of the inductor).
Hope this helps.
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