From: Terry Pinnell
Subject: Re: Need real loud anti-dog barking ultrasonic device.
Date: Fri, 13 Dec 2002 11:33:43 +0000
References: <email@example.com> <3DF73938.2C99A7B4@cern.ch> <3DF88597.60AD3446@cern.ch>
NNTP-Posting-Date: Fri, 13 Dec 2002 11:34:05 +0000 (UTC)
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Winfield Hill wrote:
> 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.
Whether my re-work is based on this approach, or another less
ambitious one like using a trimmer capacitor somewhere, how do I test
it? I raised this when designing the original, but am still unsure.
Obviously can't keep a few cats and dogs tethered up outside my
workshop. And 'scope just shows voltage across my tweeter.
Maybe I need some simplish receiving transducer that would at least
give me a reliable *indicator* of the relative output power> I could
try it with my puny device as it stands now, and then with succeeding
Or perhaps I'm dismissing the 'scope-measured voltage across the
tweeter too readily? Maybe I could get it outside the 18 V of my
supply, through resonance? But then presumably I'd have to settle for
a fixed frequency, rather than my present varying one?
Or maybe I should renew my search for pepper-spray, almost certainly
illegal in the UK.
Hobbyist, West Sussex, UK