From: Allen Mulvey <allen@amulvey.com>
To: 'Microcontroller discussion list - Public.' <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Fri, 22 May 2020 19:16:16 -0700
Subject: RE: [EE] Light bulb moment (literally)
Thread-Topic: [EE] Light bulb moment (literally)
Thread-Index:
 AQFslht8Dajw1C5ZmrYKOcqKRcNsOQFeL40wAaIQowUCBNjiGwMm0CpUqUbEJZA=
Message-ID: <000801d630a8$2395d7f0$6ac187d0$@amulvey.com>
References:
 <CAFo_nNrvRiu=-bdnTbAVcnBc1Ev5JrUCb3v5VzZX4AqGTkPrqg@mail.gmail.com>
	<CAO2TaQdywaxcWhTbrsRZLogibZXpe3+cR0d2acRZEXUYWRuD+Q@mail.gmail.com>
	<CAB115wESoi-r7a1iB6NjgJDJPBYSBxVYKASVwLzMRO7=9cqd8Q@mail.gmail.com>
	<CADHfTmO9YxiHt6pE_wAojSWUQ0-6+=320ZzUG1LGe+0k1MoyYA@mail.gmail.com>
	<CAFo_nNppaAHKJcg-j_Zd=x+rRS5YmoSUo=BeEkK83YXU1JVdUQ@mail.gmail.com>
In-Reply-To:
 <CAFo_nNppaAHKJcg-j_Zd=x+rRS5YmoSUo=BeEkK83YXU1JVdUQ@mail.gmail.com>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
Content-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: Pass (protection.outlook.com: domain of amulvey.com designates
	24.169.71.174 as permitted sender) receiver=protection.outlook.com;
	client-ip=24.169.71.174; helo=mulvey.us;
dkim-signature: v=1; c=relaxed/relaxed;
	h=from:to:references:in-reply-to:subject:date:message-id:mime-version:content-type:content-transfer-encoding;
	d=amulvey.com; s=amulvey; a=rsa-sha256;
	bh=9sl5B+VkpEXvqDwmd/DyNNz5GGEte0l8LqtYnytzZW4=;
	b=BYCUxXRp+9LhlbkljJteuYnbF/ROD048vNuWtol2tITATet0Pc6zdCyh0eucQf602
	1AXryjcHiabqt84pyEd0bLbIvRexbi8maviZly33gUmI8ETXIshWf0hKJ98iYdK/mRB
	qcFNGDJ8BP9UgJsAVFgMK5g8xVWNz7Kxqt3VTYg=;
authentication-results: spf=pass (sender IP is 24.169.71.174)
	smtp.mailfrom=amulvey.com; mit.edu; dkim=pass (signature was verified)
	header.d=amulvey.com;mit.edu; dmarc=bestguesspass action=none
	header.from=amulvey.com;compauth=pass reason=109
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-topics: [EE]
x-mailman-approved-at: Fri, 22 May 2020 22:32:12 -0400
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

I can see how this would happen. Most electrolytic capacitors have the
negative lead marked. But tantalums have the positive lead marked. Why do
everything the same when you can have so much fun the other way.

Allen

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
David C Brown
Sent: Friday, May 22, 2020 2:51 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Light bulb moment (literally)

I once had a desperate phone call from the operator of our special purpose
computer that bangs and smoke were coming out of the machine.
Turned out that a lot of tantalums had been put in the wrong way round. and
were dying noisily.

__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak                           Phone: 01663 733236
Derbyshire                eMail: dcb.home@gmail.com
SK23 7ND          web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*


On Fri, 22 May 2020 at 16:40, mike brown <mike@n5qmg.com> wrote:

> I built a prop for an escape room and had to use one of these dynamos to
> power the circuit when the player pedalled a bicycle.  It generated well
> over 36V when pedalled hard.  You should have heard the tantalum capacito=
r
> explode in testing.  Sounded like a rifle going off.
>
> On Fri, May 22, 2020, 10:29 David VanHorn <microbrix@gmail.com> wrote:
>
> > My first bike had a combination bulb and fluorescent light.  6: tube.
The
> > generator had the usual 6V output for the bulb and 100V for the tube.
> > Never seen one like that since.  This was around 1967 or 68
> >
> >
> > On Fri, May 22, 2020 at 9:19 AM Chris McSweeny <cpmcsweeny@gmail.com>
> > wrote:
> >
> > > It is, except that the maximum voltage is speed dependent. It is
> (was?) a
> > > common modification to use one to supply 12V across two lights in
> series,
> > > but with a switch to short out one of the lights at lower speeds wher=
e
> > the
> > > dynamo can't supply 12V.
> > >
> > > On Fri, May 22, 2020 at 9:34 AM David C Brown <dcb.home@gmail.com>
> > wrote:
> > >
> > > > I have just realised that the traditional "dynamo" used for bicycle
> > > > lighting (and which is really) a magneto) is, despite being sold as
> a 6
> > > > volt machine,  a actually a constant current device.
> > > > Since both voltage and frequency - hence reactance - rise
> > > > approximately linearly with speed the current remains constant.
> > > > __________________________________________
> > > > David C Brown
> > > > 43 Bings Road
> > > > Whaley Bridge
> > > > High Peak                           Phone: 01663 733236
> > > > Derbyshire                eMail: dcb.home@gmail.com
> > > > SK23 7ND          web: www.bings-knowle.co.uk/dcb
> > > > <http://www.jb.man.ac.uk/~dcb>
> > > >
> > > >
> > > >
> > > > *Sent from my etch-a-sketch*
> > > > --
> > > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > > > View/change your membership options at
> > > > http://mailman.mit.edu/mailman/listinfo/piclist
> > > >
> > > --
> > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > > View/change your membership options at
> > > http://mailman.mit.edu/mailman/listinfo/piclist
> > >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.