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#1
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Reduce the L to reduce the resistive loss - the essence of L
is the energy stored in its current carrying, and it is the current that causes I^2 R losses. The energy stored in the C is static. (Yes, there are some losses in polarising the dielectrics but these are small enough to be ignored) "Paul Burridge" wrote in message ... ISTR that one can improve Q in resonant tanks by having a low L-C ratio. Or was it high L-C ratio. I can't remember but need to know. |
#2
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Reduce the L to reduce the resistive loss - the essence of L
is the energy stored in its current carrying, and it is the current that causes I^2 R losses. The energy stored in the C is static. (Yes, there are some losses in polarising the dielectrics but these are small enough to be ignored) "Paul Burridge" wrote in message ... ISTR that one can improve Q in resonant tanks by having a low L-C ratio. Or was it high L-C ratio. I can't remember but need to know. |
#3
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Tank circuits: achieving maximum Q
Hi guys,
ISTR that one can improve Q in resonant tanks by having a low L-C ratio. Or was it high L-C ratio. I can't remember but need to know. Can any kind soul help me out? Thanks. p. -- The BBC: Licensed at public expense to spread lies. |
#4
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Airy,
What you said would be relevant only if you were trying to determine circuit losses due to "unloaded" Q of the components. I believe Paul is trying to determine the 'loaded" Q in order to obtain best selectivity (narrowest bandwidth). Is this true Paul? In order to obtain maximum selectivity, the loaded Q needs to be as high as possible. In the case of a resonant 'tank', the tank reactances are loaded by the external environment. The circuit Q (or 'loaded' Q) in this case is Q=R/X. In order to maximize loaded Q, the X term (reactance) needs to be minimized. This means low L and high C. In any case, the actual circuit losses will be a function of the ratio of unloaded Q (Q of the components) to loaded Q. The higher the unloaded Q of the components, the lower the losses in the circuit. Joe W3JDR "Airy R. Bean" wrote in message ... Reduce the L to reduce the resistive loss - the essence of L is the energy stored in its current carrying, and it is the current that causes I^2 R losses. The energy stored in the C is static. (Yes, there are some losses in polarising the dielectrics but these are small enough to be ignored) "Paul Burridge" wrote in message ... ISTR that one can improve Q in resonant tanks by having a low L-C ratio. Or was it high L-C ratio. I can't remember but need to know. |
#5
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Airy,
What you said would be relevant only if you were trying to determine circuit losses due to "unloaded" Q of the components. I believe Paul is trying to determine the 'loaded" Q in order to obtain best selectivity (narrowest bandwidth). Is this true Paul? In order to obtain maximum selectivity, the loaded Q needs to be as high as possible. In the case of a resonant 'tank', the tank reactances are loaded by the external environment. The circuit Q (or 'loaded' Q) in this case is Q=R/X. In order to maximize loaded Q, the X term (reactance) needs to be minimized. This means low L and high C. In any case, the actual circuit losses will be a function of the ratio of unloaded Q (Q of the components) to loaded Q. The higher the unloaded Q of the components, the lower the losses in the circuit. Joe W3JDR "Airy R. Bean" wrote in message ... Reduce the L to reduce the resistive loss - the essence of L is the energy stored in its current carrying, and it is the current that causes I^2 R losses. The energy stored in the C is static. (Yes, there are some losses in polarising the dielectrics but these are small enough to be ignored) "Paul Burridge" wrote in message ... ISTR that one can improve Q in resonant tanks by having a low L-C ratio. Or was it high L-C ratio. I can't remember but need to know. |
#6
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On Sun, 21 Mar 2004 16:02:18 GMT, "W3JDR" wrote:
Airy, What you said would be relevant only if you were trying to determine circuit losses due to "unloaded" Q of the components. I believe Paul is trying to determine the 'loaded" Q in order to obtain best selectivity (narrowest bandwidth). Is this true Paul? Some clarification is necessary! The application is the tank in a frequency multiplier. I am seeking to select for the 5th harmonic. Therefore, the tank needs to have as little loss as possible given the fact that the 5th will be way down dB-wise on the fundamental. I can't afford to attenuate it too much as it's already weak to begin with. Ergo, I need the lowest loss components and the best selectivity for the desired 5th harmonic. Thanks, p. -- The BBC: Licensed at public expense to spread lies. |
#7
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On Sun, 21 Mar 2004 16:02:18 GMT, "W3JDR" wrote:
Airy, What you said would be relevant only if you were trying to determine circuit losses due to "unloaded" Q of the components. I believe Paul is trying to determine the 'loaded" Q in order to obtain best selectivity (narrowest bandwidth). Is this true Paul? Some clarification is necessary! The application is the tank in a frequency multiplier. I am seeking to select for the 5th harmonic. Therefore, the tank needs to have as little loss as possible given the fact that the 5th will be way down dB-wise on the fundamental. I can't afford to attenuate it too much as it's already weak to begin with. Ergo, I need the lowest loss components and the best selectivity for the desired 5th harmonic. Thanks, p. -- The BBC: Licensed at public expense to spread lies. |
#8
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High L/C ratio increases Q.
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#9
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High L/C ratio increases Q.
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#10
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Oops - L/R ISTR!
"K9SQG" wrote in message ... High L/C ratio increases Q. |
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