I guess this is a complaint, or at least a cautionary note: Seems like I've read postings here that incorrectly use the term "resonance".
Specifically, I've read things like "the resonant frequency of this low-pass filter is ...". (Sorry, don't have the actual postings at hand, will have to hunt for them.) The implication is that a low-pass filter (or high-pass filter for that matter) can have a resonant frequency.
It can't. A resonant circuit, technically speaking and by definition, must have both inductive (L) and capacitive (C) elements, and it is resonant when XC=XL. Since low-pass, high-pass, and other filter types only contain either C or L elements, they cannot resonate.
I also read a posting that talked about how a large electrolytic capacitor could "resonate" at a certain frequency, with a chart to illustrate. In this case, however, the explanation is that the capacitor itself contains a significant amount of inductance, so again there are both C and L elements.
I think that the writers of such things are confusing other frequencies (like cutoff or corner frequency) with resonant frequency.
This may seem like a nitpick, and maybe it is, but in fields like electronics, it's important that we all speak the same language, and that we are fairly precise about what we mean. Otherwise, confusion arises, and that's not a good thing.
Specifically, I've read things like "the resonant frequency of this low-pass filter is ...". (Sorry, don't have the actual postings at hand, will have to hunt for them.) The implication is that a low-pass filter (or high-pass filter for that matter) can have a resonant frequency.
It can't. A resonant circuit, technically speaking and by definition, must have both inductive (L) and capacitive (C) elements, and it is resonant when XC=XL. Since low-pass, high-pass, and other filter types only contain either C or L elements, they cannot resonate.
I also read a posting that talked about how a large electrolytic capacitor could "resonate" at a certain frequency, with a chart to illustrate. In this case, however, the explanation is that the capacitor itself contains a significant amount of inductance, so again there are both C and L elements.
I think that the writers of such things are confusing other frequencies (like cutoff or corner frequency) with resonant frequency.
This may seem like a nitpick, and maybe it is, but in fields like electronics, it's important that we all speak the same language, and that we are fairly precise about what we mean. Otherwise, confusion arises, and that's not a good thing.