Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: Frank Krygowski <frkrygow@sbcglobal.net>
Newsgroups: rec.bicycles.tech
Subject: Re: For those who believe in electricity
Date: Tue, 8 Apr 2025 12:33:27 -0400
Organization: A noiseless patient Spider
Lines: 42
Message-ID: <vt3j4p$2jp43$2@dont-email.me>
References: <vsvct9$2gcvj$1@dont-email.me> <vt0q7i$3vi0o$5@dont-email.me>
 <vt0sik$4nkm$1@dont-email.me>
Reply-To: frkrygow@gmail.com
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Tue, 08 Apr 2025 18:33:30 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="0712508ff08c12273f2047ab212600d3";
	logging-data="2745475"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+4n3LRGVDLDB5gIq56Lx177wxiUrhG7qQ="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:5I+CEgkFNbhiWDnE5XSjt9chv1A=
Content-Language: en-US
In-Reply-To: <vt0sik$4nkm$1@dont-email.me>
Bytes: 2957

On 4/7/2025 11:56 AM, sms wrote:
> On 4/7/2025 8:16 AM, Zen Cycle wrote:
>> On 4/6/2025 10:22 PM, Frank Krygowski wrote:
> 
> <snip>
> 
> A battery puts out DC, it does not provide "half of a sine wave."
> 
> An LED dynamo light would be rectifying the AC into DC, though there are 
> ways around this if the light has multiple LEDs (two LEDs each 
> conducting for half the cycle). If there is only a single LED it can 
> still be powered by the AC from the dynamo but it would be wasteful as 
> it would only be lit for half the cycle.

First, here's what I said: "I had hoped to diagnose it using DC, 
figuring a 6 volt battery would essentially supply half of the sine wave 
so half of the input circuit. That naturally works with incandescents, 
and it worked with one Avenir LED dyno headlight that I repaired."

My reference to "essentially half the sine wave" meant that electron 
flow from a DC battery would be in the same direction as the flow during 
half the sine wave, and might serve to determine what part of the 
circuit was open.

And as I said, the DC source has worked with other LED dyno headlights. 
It works with the Avenir I own, it works with a B&M Lyt that I just 
tested. Both are single LED headlamps. It didn't work with the B&M Eyc 
I'm trying to repair. But maybe that's related to its inconsistent and 
intermittent fault.

As I mentioned in discussions here years ago, one LED dyno headlight I 
own has a very simple circuit: IIRC just a bridge rectifier, a voltage 
regulator, a resistor and a capacitor feeding one LED.

It's obvious from my photos of this B&M lamp that the electronics are 
much more complicated. I'm disappointed that the electronics experts 
here have never commented on what the likely functions of all that 
complexity.


-- 
- Frank Krygowski