A
Andre Jute
Guest
On Mar 20, 8:15 pm, SMS <[email protected]> wrote:
> Andre Jute wrote:
> > Eh? Why no? What Bob has done is clever. I did it too, without ever
> > having heard of Bob. Now that I've read it, I like his simple
> > explanation and his simple diagram: makes everything brilliantly
> > clear.
>
> I've seen these set ups and they flicker as the LEDs alternate being
> illuminated. If he's eliminated the flickering, and isn't reverse
> biasing the LEDs, then I stand corrected.
Forget about reverse biassing the LED -- well, forget about it unless
you're stupid and overdo things, in which case internet advice will do
you no good anyway; think of it as something you can risk doing within
reason, as you can overvolt halogen lamps.
As for the flicker, that's just given me an idea, because I want a
front blinkie that operates off a dynamo... But you don't need to have
the flicker. What you do is add enough pairs effectively to turn the
LEDs themselves into a rectifier. Thank of what a rectifier does: it
flattens the peaks to reduce the distance between the troughs and the
peaks of the frequency wave. Seriesed parallel pairs of LEDs just do
it on both the positive and negative going cycles. A point we haven't
discussed yet is that there will always be flicker, albeit above the
frequency of human perception; it is called ripple.
> I didn't continue the experiment because I'm not having
> > anything that ugly on my bike, but that's an aesthetic judgement,
> > nothing to do with electronics that work. (It's a different matter
> > that my next experiment, an overvolted 20W MR16 operated on batteries,
> > provided *vastly more* light.)
>
> It would be nice to have a hybrid system without having two separate
> fixtures. A battery powered MR16 lamp for a "seeing" lamp, and a dynamo
> powered lamp for a "being seen" light or simply as a back-up in case
> your batteries go dead. You could also choose to charge the battery of
> the MR16, at least partially, from the generator. A "plug-in" hybrid
> type solution.
I looked into the ways in which people do that sort of thing. My
specialty in audio amps is simplification, not for cost but for purity
of sound; one of my tube amps has fewer components than the famous
Japanese GainCard. I didn't think I could simplify the plans for a
hybrid dual lighting system much if it must have so many facilities.
That much electronics just adds to uncertainty and unreliability on
the bike. That is why I went to the series-parallel mounting: it is
the minimum configuation (see the schematic Bob published -- it makes
the point of minimal engineering at a single glance); every part of it
performs at least three functions and the number of components is
irreducable. Yeah, I know, that sort of thing sends the electronics
engineers up the wall, but I hold most electronic engineers in rather
low esteem for their tendency to set irrelevant parameters and then to
perpetrate complicated engineering for no better reason than that it
is there to be perpetrated.
Andre Jute
Impedance is futile, you will be simulated into the triode of the
Borg. -- Robert Casey
> Andre Jute wrote:
> > Eh? Why no? What Bob has done is clever. I did it too, without ever
> > having heard of Bob. Now that I've read it, I like his simple
> > explanation and his simple diagram: makes everything brilliantly
> > clear.
>
> I've seen these set ups and they flicker as the LEDs alternate being
> illuminated. If he's eliminated the flickering, and isn't reverse
> biasing the LEDs, then I stand corrected.
Forget about reverse biassing the LED -- well, forget about it unless
you're stupid and overdo things, in which case internet advice will do
you no good anyway; think of it as something you can risk doing within
reason, as you can overvolt halogen lamps.
As for the flicker, that's just given me an idea, because I want a
front blinkie that operates off a dynamo... But you don't need to have
the flicker. What you do is add enough pairs effectively to turn the
LEDs themselves into a rectifier. Thank of what a rectifier does: it
flattens the peaks to reduce the distance between the troughs and the
peaks of the frequency wave. Seriesed parallel pairs of LEDs just do
it on both the positive and negative going cycles. A point we haven't
discussed yet is that there will always be flicker, albeit above the
frequency of human perception; it is called ripple.
> I didn't continue the experiment because I'm not having
> > anything that ugly on my bike, but that's an aesthetic judgement,
> > nothing to do with electronics that work. (It's a different matter
> > that my next experiment, an overvolted 20W MR16 operated on batteries,
> > provided *vastly more* light.)
>
> It would be nice to have a hybrid system without having two separate
> fixtures. A battery powered MR16 lamp for a "seeing" lamp, and a dynamo
> powered lamp for a "being seen" light or simply as a back-up in case
> your batteries go dead. You could also choose to charge the battery of
> the MR16, at least partially, from the generator. A "plug-in" hybrid
> type solution.
I looked into the ways in which people do that sort of thing. My
specialty in audio amps is simplification, not for cost but for purity
of sound; one of my tube amps has fewer components than the famous
Japanese GainCard. I didn't think I could simplify the plans for a
hybrid dual lighting system much if it must have so many facilities.
That much electronics just adds to uncertainty and unreliability on
the bike. That is why I went to the series-parallel mounting: it is
the minimum configuation (see the schematic Bob published -- it makes
the point of minimal engineering at a single glance); every part of it
performs at least three functions and the number of components is
irreducable. Yeah, I know, that sort of thing sends the electronics
engineers up the wall, but I hold most electronic engineers in rather
low esteem for their tendency to set irrelevant parameters and then to
perpetrate complicated engineering for no better reason than that it
is there to be perpetrated.
Andre Jute
Impedance is futile, you will be simulated into the triode of the
Borg. -- Robert Casey
