| Electronics > Beginners |
| Identify speaker |
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| fixit7:
This is from a cordless phone. I think it is a speaker. Phone uses 2.4 volt battery. I was wondering if it would work in a 9 Vdc circuit? https://www.dropbox.com/s/yy6rwm0vib91010/PhoneSpeaker.jpg?dl=0 |
| PA0PBZ:
Yes it is a speaker, and the characteristics are printed on it. Since a speaker is driven with AC your question about 9V DC is irrelevant. |
| mikerj:
--- Quote from: PA0PBZ on May 25, 2019, 06:45:20 pm ---Yes it is a speaker, and the characteristics are printed on it. Since a speaker is driven with AC your question about 9V DC is irrelevant. --- End quote --- Not entirely irrelevant. A 9v pk-pk signal across that 150ohm speaker would be around 68mw, more than double it's rated power. A high impedance driver like that could be driven directly from the output of an op-amp. |
| fixit7:
--- Quote from: PA0PBZ on May 25, 2019, 06:45:20 pm ---Yes it is a speaker, and the characteristics are printed on it. Since a speaker is driven with AC your question about 9V DC is irrelevant. --- End quote --- Was not aware it was an AC speaker. |
| Zero999:
--- Quote from: fixit7 on May 25, 2019, 08:42:14 pm --- --- Quote from: PA0PBZ on May 25, 2019, 06:45:20 pm ---Yes it is a speaker, and the characteristics are printed on it. Since a speaker is driven with AC your question about 9V DC is irrelevant. --- End quote --- Was not aware it was an AC speaker. --- End quote --- All speakers need to be driven from AC. The sound they produce mirrors the AC waveform. For example put in 1VAC at 1kHz and it will produce a 1kHz tone. There are limits of course the the upper and lower ends of the frequency response. This telephone speaker is probably only good for a narrow frequency range of 300Hz to 3kHz. The only things which beep and work off DC are buzzers, basically a simple speaker with a built-in oscillator which converts the applied DC voltage to AC to drive the speaker. The oscillator in a buzzer can be either electronic (normally just a transistor with feedbacl) or electromechanical: basically a relay with a normal closed contact wired in series with the coil and the moving iron attached to a diaphragm to improve the coupling of the vibrations to the air. |
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