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Somebody
Apprentece

8 Posts
Posted - Jul 19 2009 :  4:25:57 PM  Show Profile  Reply with Quote
I made a horn with UM3561 and it have oputput for spiker.Maximum output voltage is 12V. But the problem ist that the horn is to silent. I need an amplifier for that horn and it must have 12V supply voltage.

Thanks for help.


(Edit...Move to Sound/Radio)

audioguru
Nobel Prize Winner

Canada
4218 Posts
Posted - Jul 19 2009 :  9:00:39 PM  Show Profile  Reply with Quote
The datasheet of the sound generator shows exactly how to connect it.
The datasheet shows that a supply of 12V will destroy it.

Why don't you attach your schematic so we can see what is wrong?

Is a "spiker" actually bad spelling for a speaker?
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Somebody
Apprentece

8 Posts
Posted - Jul 20 2009 :  05:17:45 AM  Show Profile  Reply with Quote
Here is the shematic for 12V version. http://www.reber.si/zvocni_efekti/UM3561/UM3561-12V.sch-200dpi.gif
The spiker is for car alarm and I think that is good, if you mean that.
The horn works properly, but it is to silent, so I need a way how to decrease the output signal.
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audioguru
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Canada
4218 Posts
Posted - Jul 20 2009 :  08:17:29 AM  Show Profile  Reply with Quote
I don't know what is a "spiker". Your schematic shows an 8 ohm speaker.
If the sound from the speaker is not loud enough then you need to increase the output signal, not decrease it.

A car horn is very loud. But your circuit feeds a square-wave with a voltage of 13V into 8 ohms which is a power of only 21W peak or only 10.6W average.

If you feed the signal to both ends of the speaker (with one end inverted) then the power will be 4 times more. Then there will not be DC so the speaker will work better.
If you use a 4 ohm speaker then the power will be doubled to 80W.

I don't know if the sound generator can drive your 1k base resistor so I increased it and increased the collector resistor.

Download Attachment: car horn.PNG
27.26 KB
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Somebody
Apprentece

8 Posts
Posted - Jul 20 2009 :  09:30:21 AM  Show Profile  Reply with Quote
I mean speaker. I'm doing mistakes, because my english is very bad.
So I will do the changes and try it on the protoboard. Will your version work with 4Ohm speaker?
Edited by - Somebody on Jul 20 2009 09:42:13 AM
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audioguru
Nobel Prize Winner

Canada
4218 Posts
Posted - Jul 20 2009 :  7:15:27 PM  Show Profile  Reply with Quote
Two IRF9540 Mosfets can easily drive a 4 ohm speaker in my circuit. The peak power is 160W and the average power is 80W.
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Somebody
Apprentece

8 Posts
Posted - Jul 21 2009 :  02:06:18 AM  Show Profile  Reply with Quote
quote:
Originally posted by audioguru

Two IRF9540 Mosfets can easily drive a 4 ohm speaker in my circuit. The peak power is 160W and the average power is 80W.


That's nice.
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Somebody
Apprentece

8 Posts
Posted - Aug 03 2009 :  1:13:25 PM  Show Profile  Reply with Quote
I'm not certain if that will work, because the speaker is not atached to GND, as it was on the first shematic? Will it work 100%?
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audioguru
Nobel Prize Winner

Canada
4218 Posts
Posted - Aug 03 2009 :  6:45:50 PM  Show Profile  Reply with Quote
You are correct.
My circuit will not work.
Each Mosfet needs to be a push-pull stage.
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Somebody
Apprentece

8 Posts
Posted - Aug 04 2009 :  08:44:01 AM  Show Profile  Reply with Quote
So I must connect the drain of first mosfet to ground and put a speaker between the drain of second mosfet and ground.
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audioguru
Nobel Prize Winner

Canada
4218 Posts
Posted - Aug 04 2009 :  2:22:08 PM  Show Profile  Reply with Quote
quote:
Originally posted by Somebody

So I must connect the drain of first mosfet to ground and put a speaker between the drain of second mosfet and ground.

No.
The drain of the Mosfet is its output in this circuit. You never short an output to ground.
Just make the first circuit and hope that the DC in the speaker does not destroy it.
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