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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