Connecting buzzer

[denny]

Does it possible to connect mobile phone speaker(buzzer) to PC Audio Out?(to
test sound on buzzer). If to solder wires to buzzer and connect it to Audio
Out via a 3.5mm stereo jack: Will the audio output signal level fit small
phone buzzer?

 

[Paul]

Does it possible to connect mobile phone speaker(buzzer) to PC Audio Out?(to
test sound on buzzer). If to solder wires to buzzer and connect it to Audio
Out via a 3.5mm stereo jack: Will the audio output signal level fit small
phone buzzer?

The short answer is, it won't work well.

You may get some sound from it, but it won't be room filling.

I based my answer, on finding some examples of mobile phone speakers
with a rating of 1 watt of sound, with 8 ohm impedance, implying they
are regular speakers with a coil inside. Some speakers may use
piezoelectric devices instead, and would have different characteristics.

*******

I checked one advert for a mobile phone speaker, and it was
rated "1 watt" audio output, with a speaker impedance of 8 ohms.

Computers have line level audio, roughly around 1 volt RMS output.
Sometimes they manage a little bit more than that, but not by much.

Built-in sound, takes the form of AC'97 CODEC chip or HDAudio CODEC
chip. There is a typical datasheet you can download on this page,
with representative values. ( ALC850_DataSheet_1.4.pdf , 597,887 bytes )

http://www.realtek.com.tw/downloads...=59&DownTypeID=1&GetDown=false&Downloads=true

Typical built-in sound solutions, don't come with a "power amplifier".
The sound chips typically have headphone drive, and even that may
be restricted to the green Line-Out jack. This can manage to
drive 1 volt RMS into 32 ohms (32 ohms being a typical headphone
impedance). The RealTek part manages "50 milliwatts into 20 ohms".
That would represent a slight stronger drive level (lower ohms
value in that case, being stronger). Using V**2 over R the resistance,
that would correspond to 1**2/20 = 1/20 = 0.050, so we know
the specification is saying the output is 1 volt RMS in that
case.

The datasheets aren't really that well specified. They don't show
power output curves for example.

The theory says, maximum power transfer happens, when the load
matches the output impedance of the amplifier. Page 49 of the
datasheet, claims the output impedance is 5 ohms. Which means it
should work well with an 8 ohm mobile speaker (in terms of
transferring the available power, which isn't much). The second data
point is "Amplifier Maximum Output Power", which is 50 milliwatts
with a 20 ohm load. You would think it would make sense to quote
the power available at 5 ohms instead, but that's not how they did it.

In any case, barring the tiny technical details, I'd say you can't
expect to get more than about 50 milliwatts of audio power.
That is 0.050 watts. Now, compare that to the average table radio,
which would be 2 watts output. 2 watts output is sufficient to
produce "room filling sound". Not loud enough to hurt your eardrums,
but loud enough to be heard. 0.050 watts is 40 times less than that.
So that should give you some perspective on what kind of sound level
to expect. It'll be weak.

Another annoying detail, is they don't say what happens if you short
circuit the computer output on the 3.5mm jack. Some chips will state
they can withstand a short circuit indefinitely on one output signal,
but I can't find such a description in a couple different CODEC data
sheets. So you'd want to take some care, when making your electrical
connections.

You may get enough sound, to prove the speaker works, but not
enough sound to actually use it to listen to music...

A small speaker will not have a very good frequency response.
When using the computer for the audio test, select a tone around
2KHz or so as a test. The mobile speaker will be optimized for
voice frequencies, and the speaker might have no low frequency
response to speak of. If you tested with a 100Hz signal, you
might not hear anything.

Paul

 

[denny]

The short answer is, it won't work well.

You may get some sound from it, but it won't be room filling.

I based my answer, on finding some examples of mobile phone speakers
with a rating of 1 watt of sound, with 8 ohm impedance, implying they
are regular speakers with a coil inside. Some speakers may use
piezoelectric devices instead, and would have different characteristics.

*******

I checked one advert for a mobile phone speaker, and it was
rated "1 watt" audio output, with a speaker impedance of 8 ohms.

Computers have line level audio, roughly around 1 volt RMS output.
Sometimes they manage a little bit more than that, but not by much.

Built-in sound, takes the form of AC'97 CODEC chip or HDAudio CODEC
chip. There is a typical datasheet you can download on this page,
with representative values. ( ALC850_DataSheet_1.4.pdf , 597,887 bytes )

http://www.realtek.com.tw/downloads...=59&DownTypeID=1&GetDown=false&Downloads=true

Typical built-in sound solutions, don't come with a "power amplifier".
The sound chips typically have headphone drive, and even that may
be restricted to the green Line-Out jack. This can manage to
drive 1 volt RMS into 32 ohms (32 ohms being a typical headphone
impedance). The RealTek part manages "50 milliwatts into 20 ohms".
That would represent a slight stronger drive level (lower ohms
value in that case, being stronger). Using V**2 over R the resistance,
that would correspond to 1**2/20 = 1/20 = 0.050, so we know
the specification is saying the output is 1 volt RMS in that
case.

The datasheets aren't really that well specified. They don't show
power output curves for example.

The theory says, maximum power transfer happens, when the load
matches the output impedance of the amplifier. Page 49 of the
datasheet, claims the output impedance is 5 ohms. Which means it
should work well with an 8 ohm mobile speaker (in terms of
transferring the available power, which isn't much). The second data
point is "Amplifier Maximum Output Power", which is 50 milliwatts
with a 20 ohm load. You would think it would make sense to quote
the power available at 5 ohms instead, but that's not how they did it.

In any case, barring the tiny technical details, I'd say you can't
expect to get more than about 50 milliwatts of audio power.
That is 0.050 watts. Now, compare that to the average table radio,
which would be 2 watts output. 2 watts output is sufficient to
produce "room filling sound". Not loud enough to hurt your eardrums,
but loud enough to be heard. 0.050 watts is 40 times less than that.
So that should give you some perspective on what kind of sound level
to expect. It'll be weak.

Another annoying detail, is they don't say what happens if you short
circuit the computer output on the 3.5mm jack. Some chips will state
they can withstand a short circuit indefinitely on one output signal,
but I can't find such a description in a couple different CODEC data
sheets. So you'd want to take some care, when making your electrical
connections.

You may get enough sound, to prove the speaker works, but not
enough sound to actually use it to listen to music...

A small speaker will not have a very good frequency response.
When using the computer for the audio test, select a tone around
2KHz or so as a test. The mobile speaker will be optimized for
voice frequencies, and the speaker might have no low frequency
response to speak of. If you tested with a 100Hz signal, you
might not hear anything.

Paul

--------

I need not for listening the music, but to simulate phone speaker sound, in
order to adjust audio file to better fit nokia 2610 phone speaker.

http://www.u2ugsm.com/downloads/repairign/nokia/1600-buzzer-ways.jpg
http://www.mobilephone-spares.com/Nokia-1110i-Speaker.html

Can the B2101 speaker directly connected to PC Audio Out?


Regards

 

[Paul]

I need not for listening the music, but to simulate phone speaker sound, in
order to adjust audio file to better fit nokia 2610 phone speaker.

http://www.u2ugsm.com/downloads/repairign/nokia/1600-buzzer-ways.jpg
http://www.mobilephone-spares.com/Nokia-1110i-Speaker.html

Can the B2101 speaker directly connected to PC Audio Out?


Regards

The first picture (1600-buzzer-ways.jpg) shows the usage of a TPA2010
power amplifier chip. That chip can drive up to 2.5 W to the tiny speaker.

http://focus.ti.com/lit/ds/symlink/tpa2010d1.pdf

Your computer audio output simply is not as strong as that.
You may get a tiny sound from it, and maybe that is proof the
speaker is still working. I would disconnect the speaker from
the mobile circuit board, before doing a test.

If you wish to simulate entirely, the sound of the mobile
phone, you should use a small amplifier to drive it.
Kits are available, with the same kind of power output as
a TPA2010.

This kit provides a 2 x 1W power amplifier. This might be a little
on the weak side.

http://www.canakit.com/mini-walkman-stereo-amplifier-kit-ck122-uk122.html

This is a 7 watt monophonic amplifier, which would be suitable
for driving the mobile speaker with more sound. Since the power
output capability exceeds the rating of the speaker, you can't
turn the volume control all the way up. In reality, you never
really get 7 watts from a circuit like this.

http://www.canakit.com/5w-audio-amplifier-kit-ck153-uk153.html

The computer does not have that amplifier chip inside, and that
is why you'd generally need an external amplifier, if you
expect a good sound level.

*******

If you want to connect the 8 ohm load to the computer, go ahead.
Use the program Audacity, to send a continuous tone to Line-Out.
Connect the speaker for a short interval and listen for a
response. What I cannot promise you, is how much abuse the
computer sound chip can take. Use an amplifier, for any
serious application of the speaker.

*******

I built one of these, and while it is rated at 40W, in
a typical situation, I seem to be getting 2W per channel (measured).
This is partially due to my usage of 8 ohm speakers. If I
connected 2 ohm speakers, I would be able to drive more
power into the speaker. The potential power output is also
related to the supply voltage, and I'm running this off
a 12V linear regulator. This particular kit can be run at
up to 18V or so.

http://www.canakit.com/40w-bridged-stereo-audio-amplifier-kit-ck194-uk194.html

Paul

 

[Paul]

I need not for listening the music, but to simulate phone speaker sound, in
order to adjust audio file to better fit nokia 2610 phone speaker.

http://www.u2ugsm.com/downloads/repairign/nokia/1600-buzzer-ways.jpg
http://www.mobilephone-spares.com/Nokia-1110i-Speaker.html

Can the B2101 speaker directly connected to PC Audio Out?


Regards

I tested an 8 ohm speaker, directly with the Line Out from the
computer, and I was surprised to find the sound level was audible.
There seems to be enough power level to make it work.

I did not test it for long, and I don't know if the audio chip
(CODEC) would like that electrical load for long periods of time.

I tried the Audacity program, had it generate a 440Hz tone, and used that to
test my speaker. Amplitude set to 1.0. Both Master and Wave volume
controls set to 100%.

http://audacity.sourceforge.net/

As long as your CODEC chip does not burn out, it seems to work.
I tested mine for only a couple of seconds. Using an amplifier
between the computer and the speaker, reduces the risk of
damage.

Paul

 

[denny]

I tested an 8 ohm speaker, directly with the Line Out from the
computer, and I was surprised to find the sound level was audible.
There seems to be enough power level to make it work.

I did not test it for long, and I don't know if the audio chip
(CODEC) would like that electrical load for long periods of time.

I tried the Audacity program, had it generate a 440Hz tone, and used that to
test my speaker. Amplitude set to 1.0. Both Master and Wave volume
controls set to 100%.

http://audacity.sourceforge.net/

As long as your CODEC chip does not burn out, it seems to work.
I tested mine for only a couple of seconds. Using an amplifier
between the computer and the speaker, reduces the risk of
damage.

Paul

----------

thanks for info. Will try to get an appropriate amplifier. Is the nokia
2610 buzzer 8 Ohm?

Regards,

 

[Paul]

----------

thanks for info. Will try to get an appropriate amplifier. Is the nokia
2610 buzzer 8 Ohm?

Regards,

I could not find data on the Nokia part. When the Chinese manufacturers
make substitute parts, they seldom state the hardware parameters.
(The Alibaba chinese site contains lots of replacement parts, with
no useful specs.) Nokia itself, has no reason to release such
information to the public.

Paul