4 ms·

In the case you're talking about, impedance means "characteristic impedance", i.e., one parameter which (along with speed of light in the given medium and lengt

by kwantam 15y ago

In the case you're talking about, impedance means "characteristic impedance", i.e., one parameter which (along with speed of light in the given medium and length) defines the behavior of a transmission line. [1] It is the same thing in the sense that mathematically both are a complex (i.e., Real plus Imaginary) relationship between voltage and current. However, a transmission line is a two-port network while a capacitor is a one-port network, so these two senses of impedance correspond to different physical phenomena. In a capacitor, the impedance defines the relationship between voltage and current at the port (i.e., between the two terminals of the cap; this is sometimes called the driving point impedance). For a transmission line, the characteristic impedance defines, among other things, the equivalent impedance seen at one end of the line when the line is either infinitely long or an integral number of wavelengths long and terminated at the other end by an impedance of the same value as the characteristic impedance. Instrument cables do indeed carry AC signals, inasmuch as the signal on the line corresponds to the frequency of the note(s) you're playing. AC is just "non-zero frequency"---any signal which is not a constant, unchanging (DC) value is considered AC. So, 50/60Hz line power is an AC signal, the 2.4GHz signals used by your 802.11 network card are AC, and middle C (261.6 Hz) is AC. [1] http://en.wikipedia.org/wiki/Characteristic_impedance http://en.wikipedia.org/wiki/Characteristic_impedance

lcargill99 15y ago
At audio frequencies, characteristic impedance is almost always irrelevant. hi-Z is a crystal mic, guitar pickup or crystal phono pickup source.lo-Z is a dynamic or condenser mic source. Obviously, a preamp may be used as an impedance converter to lower hi-Z to loZ. There's such a preamp in the condenser mic. The cables are hiZ or loZ only in that they're generally used with one source or the other. But that's by convention. loZ is usually a balanced XLR connection; hiZ is generally an unbalanced 1/4" connection. hiZ is generally at around 1 megohm. loZ is archetypally 600 ohm. Line is neither; it's 10,000 to 50 or 100k ohm.

by kwantam 15y ago

lcargill99 15y ago

At audio frequencies, characteristic impedance is almost always irrelevant. hi-Z is a crystal mic, guitar pickup or crystal phono pickup source.lo-Z is a dynamic or condenser mic source. Obviously, a preamp may be used as an impedance converter to lower hi-Z to loZ. There's such a preamp in the condenser mic. The cables are hiZ or loZ only in that they're generally used with one source or the other. But that's by convention. loZ is usually a balanced XLR connection; hiZ is generally an unbalanced 1/4" connection. hiZ is generally at around 1 megohm. loZ is archetypally 600 ohm. Line is neither; it's 10,000 to 50 or 100k ohm.