A forum site like part15.org has a main mission of sharing knowledge and experience regarding legal operation of low power radio stations, not only in the U.S., but everywhere on earth where low power radio exists.
There have been many times when members have helped KDX, my station located between the kitchen and living room, and we have tried to give other stations the best of what we've learned.
Another thread about "Low Frequency Audio Response" inspires me to open this thread as if we were running an actual school, by quizzing you, the "students".
It can be easier to present a "lesson" if we know the state of a student's knowledge, and YOU are drafted to take this quiz with no choice in the matter because it's mandatory and required of ALL part15.org members no matter how much you know or don't know about radio technology.
To make it easy I will spread the Quiz over many days asking one question at a time to which you must give your best answer. This will give us an idea what areas need to be opened for further discussion with the objective of making this the Most Effective Learning Site in the Cyber-Verse.
Also, if you have a Question you'd like answered please submit it as part of the Quiz.
Question # 1 -
What is the definition of "line level"
Take all the time you want starting now.
It's a perfectly horizontal line between two points.
Line level in electronics is a signal taken from the preamp that is constant volume unaffected by the volume control on the power amp and unaffected by the tone controls with the preamp as it is taken before this stage.
Wikipedia can provide us with a technically accurate definition, but not very useful to many of us non-techies.
In simplest terms as applied to our own needs, there are two level types we should know: LINE and MIC. LINE level is what you would typically find on an unbalanced RCA connector/jack (at -10 dB) or a balanced XLR/TRS connector (at +4 dB). MIC level is much lower, typically in the millivolt range and down about -40 to -60 dB. This will also generally be on a three-pin XLR connector, labeled as a Mic Level input.
To look at it non-scientifically, plug a microphone into the LINE LEVEL input of a garden variety mixer and you will hear practically nothing. Now plug the audio output of a CD deck into the mic input of a soundcard and revel in the distortion.
To be fair, there are two other "levels" to know but do not really affect us too much: Instrument and Speaker. I recommend looking them up, at least to demystify some of those jacks on the back of that Yamaha mixer at church.