Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Joy Joy is offline
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Default How do I prevent the fade out beep(s) when the power is cut?

I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power is
cut?

Thanks so much!

Joy
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Default How do I prevent the fade out beep(s) when the power is cut?



"Joy" wrote in message
news
I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power is
cut?

Thanks so much!

Joy



Use a transformer with a smaller filter capacitor, or connect a 12V
incandescent light bulb in parallel with the beeper to drain the charge when
power is removed. Another option is to switch the 12V with a relay rather
than switching power to the primary of the transformer.


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Default How do I prevent the fade out beep(s) when the power is cut?

On 3ÔÂ26ÈÕ, ÉÏÎç1ʱ40·Ö, "James Sweet" wrote:
"Joy" wrote in message

news
I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.


I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...


Is there a simple way to get the siren to silence as soon as the power is
cut?


Thanks so much!


Joy


Use a transformer with a smaller filter capacitor, or connect a 12V
incandescent light bulb in parallel with the beeper to drain the charge when
power is removed. Another option is to switch the 12V with a relay rather
than switching power to the primary of the transformer.




Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com












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Default How do I prevent the fade out beep(s) when the power is cut?

On Tue, 25 Mar 2008 13:40:49 -0400, James Sweet
wrote:

"Joy" wrote in message
news
I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power
is
cut?

Thanks so much!

Joy



Use a transformer with a smaller filter capacitor, or connect a 12V
incandescent light bulb in parallel with the beeper to drain the charge
when
power is removed. Another option is to switch the 12V with a relay rather
than switching power to the primary of the transformer.


Thanks for the idea! I can try the 12V bulb since that should be easy to
find (she says) and easy to do. And inexpensive. The transformer was just
lying around so I'd rather not have to use (buy) a different one.

I will try this as soon as I can. It sounds like a resistor would also
work. If so, would there be an easy way for me to calculate the resistance?

Thanks again!

Joy

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Default How do I prevent the fade out beep(s) when the power is cut?



"Joy" wrote in message
news
On Tue, 25 Mar 2008 13:40:49 -0400, James Sweet
wrote:

"Joy" wrote in message
news
I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power
is
cut?

Thanks so much!

Joy



Use a transformer with a smaller filter capacitor, or connect a 12V
incandescent light bulb in parallel with the beeper to drain the charge
when
power is removed. Another option is to switch the 12V with a relay rather
than switching power to the primary of the transformer.


Thanks for the idea! I can try the 12V bulb since that should be easy to
find (she says) and easy to do. And inexpensive. The transformer was just
lying around so I'd rather not have to use (buy) a different one.

I will try this as soon as I can. It sounds like a resistor would also
work. If so, would there be an easy way for me to calculate the
resistance?



Yeah a resistor would be fine too, you can calculate it using ohms law V=I*R
where V is the voltage, I is the current in Amps, and R is the resistance in
ohms. The I that you need depends on the size of the filter capacitor which
depends generally on the capacity of the transformer, some experimentation
may be needed.




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Default How do I prevent the fade out beep(s) when the power is cut?

Joy wrote in newsp.t8k1rkvqug52hc@user-
47b243c432.myhome.westell.com:

I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power is
cut?

Thanks so much!


Try a single pole, double throw switch.
Connect the common lead to the siren.
Connect the battery to one of the remaining contacts on the switch and
ground the other contact.

No---------------------battery
common------------------siren
Nc---------------------gnd

This way, when you 'cut the power' you will also ground the input lead
going to the siren. If there is a capacitor inside the siren, this should
discharge it and stop the siren.

Try testing first by taking the lead that connects to one end of the
battery and quickly move it to the other, so that BOTH leads touch
together. If that stops the siren, then the switch should work.






--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

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Default How do I prevent the fade out beep(s) when the power is cut?

Joy wrote in newsp.t8k1rkvqug52hc@user-
47b243c432.myhome.westell.com:

I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power is
cut?

Thanks so much!

Joy






--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap
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bz bz is offline
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Default How do I prevent the fade out beep(s) when the power is cut?

bz wrote in
98.139:

Joy wrote in newsp.t8k1rkvqug52hc@user-
47b243c432.myhome.westell.com:

I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP
as it should, but when the power is cut, the beeping fades out instead
of stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power
is cut?

Thanks so much!

Joy


one last try. Sorry. I missed seeing that you were using a 'DC
transformer'.

They have a capacitor built in that is holding a charge.

All you need to do is disconnect the siren from the power supply.
It should shut off immediately.

You should do this with a 110 vac relay.

Hook the coil of the relay in parallel with your power supply.
When the power comes on, you want the relay to close and hook the siren to
the power supply.
When the AC goes off, you want the relay to open and disconnect the siren
from the power supply.

The power supply will only use power when the beeper is activated. And you
won't be wasting power with a resistor and possibly damaging your power
supply.







--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

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Default How do I prevent the fade out beep(s) when the power is cut?

On Tue, 25 Mar 2008 14:54:35 -0400, bz wrote:

bz wrote in
98.139:

Joy wrote in newsp.t8k1rkvqug52hc@user-
47b243c432.myhome.westell.com:

I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP
as it should, but when the power is cut, the beeping fades out instead
of stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power
is cut?

Thanks so much!

Joy


one last try. Sorry. I missed seeing that you were using a 'DC
transformer'.

They have a capacitor built in that is holding a charge.

All you need to do is disconnect the siren from the power supply.
It should shut off immediately.

You should do this with a 110 vac relay.

Hook the coil of the relay in parallel with your power supply.
When the power comes on, you want the relay to close and hook the siren
to the power supply.
When the AC goes off, you want the relay to open and disconnect the siren
from the power supply.

The power supply will only use power when the beeper is activated. And
you won't be wasting power with a resistor and possibly damaging your
power
supply.



Would a 110 vac relay be activated by a 12-15V DC transformer?
And this would mean both the relay and the siren would be powered by the
same power supply (the dc transformer) except that the relay would also
switch the siren. Is this correct?

I WAS trying to be really simple which is why the light bulb or resistor
idea sounds good.

How much damage could I do by using a resistor box and starting with a
high value and slowly working down until it worked acceptably? I guess I
could damage something in the process, but how likely do you think it
would be?

Joy

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Default How do I prevent the fade out beep(s) when the power is cut?




Would a 110 vac relay be activated by a 12-15V DC transformer?
And this would mean both the relay and the siren would be powered by the
same power supply (the dc transformer) except that the relay would also
switch the siren. Is this correct?

I WAS trying to be really simple which is why the light bulb or resistor
idea sounds good.

How much damage could I do by using a resistor box and starting with a
high value and slowly working down until it worked acceptably? I guess I
could damage something in the process, but how likely do you think it
would be?

Joy



He means connect the relay to the same power source that the transformer is
connected to, and use the contacts to switch the output of the transformer.
That route occurred to me but I skipped it as it seems more complex than
other solutions.

You won't hurt anything with the resistor, just don't go so low in value
that you draw more than the transformer is rated to produce, I would try
something around 470 ohms 1/2W, that's a common value. That'll draw about
25mA and should silence the beeper immediately.




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Default How do I prevent the fade out beep(s) when the power is cut?

On 3ÔÂ26ÈÕ, ÉÏÎç1ʱ31·Ö, Joy wrote:
I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power is
cut?

Thanks so much!

Joy




Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com












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Default How do I prevent the fade out beep(s) when the power is cut? THANKS

On Tue, 25 Mar 2008 17:41:38 -0400, James Sweet
wrote:
Would a 110 vac relay be activated by a 12-15V DC transformer?
And this would mean both the relay and the siren would be powered by the
same power supply (the dc transformer) except that the relay would also
switch the siren. Is this correct?

I WAS trying to be really simple which is why the light bulb or resistor
idea sounds good.

How much damage could I do by using a resistor box and starting with a
high value and slowly working down until it worked acceptably? I guess
I
could damage something in the process, but how likely do you think it
would be?

Joy



He means connect the relay to the same power source that the transformer
is
connected to, and use the contacts to switch the output of the
transformer.
That route occurred to me but I skipped it as it seems more complex than
other solutions.

You won't hurt anything with the resistor, just don't go so low in value
that you draw more than the transformer is rated to produce, I would try
something around 470 ohms 1/2W, that's a common value. That'll draw about
25mA and should silence the beeper immediately.



Just wanted to thank you all. A 400 ohm resistor did a pretty good job of
doing what I wanted!

Joy
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Default How do I prevent the fade out beep(s) when the power is cut?

On 3ÔÂ26ÈÕ, ÉÏÎç1ʱ31·Ö, Joy wrote:
I am trying to make a beeper to plug into a sonic alert unit for a deaf
person.

I have a 12V DC transformer directly wired to a 3-20V DC beeping siren.
When the transformer is plugged in, the siren goes BEEP...BEEP...BEEP as
it should, but when the power is cut, the beeping fades out instead of
stopping immediately. BEEp...Beep...beee...

Is there a simple way to get the siren to silence as soon as the power is
cut?

Thanks so much!

Joy




Do you want access to China's massive pool of electronic
manufacturers... but lack the time to contact suppliers, negotiate
contracts, arrange shipping or monitor product quality? Don't worry -
Let seriouswholesale deal with all that for you.

*Check out the huge range of Gadgets, MP3 / MP4 Players, Car DVD /
Audio, and Computer Accessories now by visiting the online wholesale
catalog at seriouswholesale. com You'll have peace of mind thanks to
the seriouswholesale Quality Control, 12-month Warranty on all
products, and easy secure payment by credit card through Paypal.

Selling on eBay or your own online store? Send products direct from
our warehouse to your customers using our unique drop-shipping
service. You can profit by selling hundreds of different products,
without holding any of your own inventory! Any questions you have will
be answered by the seriouswholesale English-speaking customer support
team... Their aim is to make your China electronics importing business
easier to run than ever before.

Welcome to http://www.seriouswholesale.com.

seriouswholesale - Buy from the source, profit without the hassle.

- 12 Months Warranty - No minimum order restrictions - Drop-shipping
with no additional fee - Pay by safely by PayPal seriouswholesale
Wholesale Co., Ltd.: Chinas original and best online electronics
wholesaler & drop-shipper: seriouswholesale. com












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