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From: Winfield Hill
Subject: Re: Need real loud anti-dog barking ultrasonic device.
Date: 14 Dec 2002 06:37:21 -0800
Organization: Rowland Institute
References: <email@example.com> <3DF73938.2C99A7B4@cern.ch> <3DF88597.60AD3446@cern.ch>
X-Newsreader: Direct Read News 4.20
> Terry wrote...
>>Winfield Hill wrote:
>>> Jeroen wrote...
>>>> Winfield Hill wrote:
>>>>> Very nice. I like the feature allowing a lower-voltage battery.
>>>>> That reminds me, one ought to be able to use a dual MOSFET driver
>>>>> IC to more easily make such a monster beeper,
>> Win, Jeoen: In case I ever get around to building this, to replace
>> my failed low-power design, could you clarify what those 4 inductors
>> are please?
> Sorry Terry, those aren't inductors, it's one transformer with
> four windings. Or two center-tapped widings. It'd most likely
> be custom wound on an ungapped pot core. And the resonating L
> could also be made with a gapped pot-core. Along with the piezo
> transducer, the transfomer design would be a non-trivial issue.
Terry, you should go back and look at the details in Jeroen
Belleman's 'gif drawing - http://cern.ch/jeroen/misc/BEEP.gif
He's already designed a transformer: each winding was 10 turns
on a bobbin with a RM8 pot core from 3B7 ferrite. He says the
FET / transformer / resonating-inductor combo can take 30W from
a small 6V NiCd battery, creating 400V across the transducer.
>>. ___________|| ||______________________________
>>. | ||___|| |
>>. | #
>>. | Vbatt (5 to 9V) L #
>>. | ,--|<|--+-----o #
>>. | | | |
>>. | ============================================ |
>>. | +---|(-- gnd |
>>. | | | | |
>>. | | R R TC4426 |
>>. D /| | | |\ D
>>. G--+-O< |--+ +--| >O-+--G
>>. S | \| | | |/ | S
>>. | | | \ / | |
>>. gnd | gnd \/ | gnd
>>. | C /\ C |
>>. '-/\/-||-' '-||-/\/-'
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