From: mike brown <mike@n5qmg.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Fri, 22 May 2020 08:39:29 -0700
Subject: Re: [EE] Light bulb moment (literally)
Thread-Topic: [EE] Light bulb moment (literally)
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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 capacitor
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 serie=
s,
> > but with a switch to short out one of the lights at lower speeds where
> 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*
> > > --
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