Speaker & Battery: Low Voltage Effects

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When a low-voltage battery is connected to a speaker, the speaker's voice coil, acting as an inductor, may cause a brief movement of the cone, potentially producing a popping sound. This initial movement occurs due to the sudden establishment of a magnetic field, but it quickly stops as the battery discharges through the voice coil, which can lead to overheating and damage. The low power of the battery and the nature of DC current mean that the speaker will not function effectively, aligning with the understanding that it "won't work" as intended. The discussion highlights the importance of understanding the physics behind speaker operation, particularly in relation to voltage and current types. Overall, the explanation provided clarifies the behavior of speakers under low-voltage conditions.
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Homework Statement



Hey guys...I'm helping my girlfriend again, in her intro physics. We never went over this stuff, in my more advance physics. Her question is this:

What would a speaker do the instant a low-voltage battery is connected to it?

Homework Equations


The Attempt at a Solution



I am not sure...I'm guessing that it would make a humming noise...but that is just a guess. She can't find it in her book, and I'm not there to look at it. Any way of explaining it to me, so I can try to teach it to her(she needs to actually know "why"...not just the answer).

Thanks!
Brad

PS...she just typed to me, and she thinks that it just "won't work"...so, if that is the answer...haha...just say. ***Edit...Typed more to me...She thinks it won't work, due to it being a low power source, and a DC current. This makes sense to me...but then I think about car speakers, but I think they are ran through a converter/booster.
 
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The voice coil is an inductor, which is a short circuit to DC. The speaker cone would move a tiny bit the instant the battery is connected, perhaps making an audible popping sound, and then would stop moving when the magnetic field is fully established in the voice coil. The battery would then simply discharge itself through the voice coil, perhaps heating up and destroying it in the process.

- Warren
 
Wow...thanks Warren, Quick answer!

I understand what you are saying...is this the right answer for physics 101(if you understand what I'm saying)??
 
It's the right answer for Physics 101, Physics 202 and the electrical engineering industry. Indeed the universe itself approves of my answer whole-heartedly. (I asked.)

- Warren
 
Thank you...I've explained it to her...and now she "says" she understands...haah...women! I thank you...if anything else, I've learned something!
 
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