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DC buzzer/noisemaker that doesn’t use a transistor? Answered

I’ve got some nice homemade field phones I made out of old carbon microphone handsets.  I’ve currently got DC piezo buzzers for ringers (which have transistors in them).

I want to them to be able to survive an EMP, so I don’t want to use transistors.

Is there anything I can use for a DC buzzer/noisemaker that doesn’t need AC power, or a transistor?  

The voltage of the phones is 1.5v - 3v dc

 

 

Discussions

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liquidhandwash

3 years ago

Relay buzzer even without the transformer and speaker make racket if mounted on a piece of sheet metal. You can also use a small motor with a out of balance wieght on the shaft

Screen Shot 2016-02-10 at 9.32.49 PM.png

Thanks for the suggestions,

I only know some of the electronics symbols, could you tell me what the thing marked "PBS", and what's the thing marked "C" are?

thanks.

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gmoon

3 years ago

Search for "electromagnetic buzzer -piezo", i.e., filter out piezo. Wasn't so long ago that all buzzers were electromagnetic only.

Here's a reasonably nice write-up. They are super-simple: an electromagnet, with a vibrating part that makes/breaks the current to the magnet. Magnet pulls the vibrator, circuit breaks. The vibrator returns to rest, reconnecting the magnet. Repeat, ad infinitum. They work great with DC.

Pretty much the same principle applies for an old-school phone ringer or an alarm bell...

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Downunder35m

3 years ago

Use Google or simply check how the old wired phones worked.

No need to get everyone exited here if a simple Google request is all you need.
Or just order the buzzer directly from Fleabuy...

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instrucables360Downunder35m

Reply 3 years ago

Perhaps you should've done a simple google request before posting.

Old phones used a hand cranked AC dynamo, that operated the AC ringer bell.

Landline phones still work the same way but you don't need to crank a dynamo to generate the AC it's transmitted over the lines.