Re: For those who believe in electricity

On 4/9/2025 12:19 PM, Zen Cycle wrote:

On 4/9/2025 11:59 AM, Frank Krygowski wrote:

On 4/9/2025 6:53 AM, zen cycle wrote:

On 4/8/2025 6:44 PM, Frank Krygowski wrote:

On 4/8/2025 6:29 PM, Frank Krygowski wrote:

On 4/8/2025 5:15 PM, Frank Krygowski wrote:

On 4/8/2025 4:00 PM, Zen Cycle wrote:

On 4/8/2025 3:04 PM, Frank Krygowski wrote:

On 4/8/2025 1:40 PM, Zen Cycle wrote:

On 4/8/2025 12:44 PM, Frank Krygowski wrote:

On 4/7/2025 2:58 PM, Zen Cycle wrote:

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Just as a matter of personal interest, can you read the numbers off the 16 pin IC?

It has no numbers or other codes at all! It's solid black with a sort of fine stippled finish.
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Take another look. I can see 4 rows of text but the resolution on the picture isn't good enough to make it out. FWIW, it's the square device in your second picture with 4 solder joints on each side, next to the octagonal device with "220" written on it (that's a 220uH inductor, likely part of a PWM or PS switcher circuit).

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Sorry, Zen, it absolutely has no writing on it. I don't know if I can manage a micro photograph to convince you, but I'm using a high powered loupe in sunlight. It's just a stippled black finish.
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Try again, using this as a reference:
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https://1drv.ms/i/c/5c034a6b86a172e9/ EX6snfFdTeJMl1tfB4xqOUwBXw_4YXVPsbTNjw04Bpgcdw?e=lFRSWg
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4 lines of text. I think I can make out 4x35x on the first line, but that's it.

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Those are reflections. There is no text, no letters, no numbers. I'll try to get a super-closeup photo later, but this is silly.

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Here are two more shots, through a loupe:
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https://live.staticflickr.com/65535/54440036155_e9437c6d58_m.jpg
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https://live.staticflickr.com/65535/54438807352_4bb9fb0d30_m.jpg
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Honest, no text, no letters, no numbers.

Here's a larger version of the better one. I think I clicked wrong before generating that link.
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https://www.flickr.com/photos/16972296@N08/54438807352/in/ dateposted- public/
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It does seem odd to have an unlabeled 16 pin device. I can check to see if that's some sort of coating applied over some text.
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... Nope. Some fine black stuff scraped away, and the surface now looks smoother, but still no visible characters.
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I don't know what to tell you except maybe get someone with better eyesight to look at it. The First of the new photos is a good angle, I can see the lines of text but still blurry. The second and third of the new photos are a bad angle such that the light doesn't catch the text, but better resolution.
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I know Jeff has already commented about seeing the text, I'd be interested if anyone else has seen the photos and can comment.
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_All_ devices of this type are laser etched with the part number and some sort of factory/lot/date code, or at the very least with some type of abbreviated code that you can decipher with the data sheet. Some companies _do_ have devices custom built with no markings to prevent reverse engineering, but those are rare and generally restricted to higher dollar items.
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No big deal. It was just a matter of personal interest, don't bother putting anymore effort into it if you don't want to.

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I'd require a better camera to get a better photo than this:
https://www.flickr.com/photos/16972296@N08/54438807352/in/dateposted- public/
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What can I say? Using my eyes with a variety of magnifiers, I see no markings. After some light scraping, I see no markings. In the photos I see no markings. I could try heavier scraping in case B&M was very diligent about keeping their chips secret...
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But I don't see any more effort in identifying that chip is justified. It certainly has no bearing on getting the headlight to work.

 No big deal. It was just a matter of personal interest, don't bother
putting anymore effort into it if you don't want to. But there is marking on the device, it's just too blurry to read.
 

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I'm still curious if electronics people here can address the complexity of the circuit, at least in general. Any ideas what it's all for?

 Answered this morning:
https://news.novabbs.org/tech/article-flat.php? id=123713&group=rec.bicycles.tech#123713
   I'll

remind you that I do have some LED dynamo headlights that light up when I apply DC. This one does not. Is that a clue to what the circuit is doing?

 That's difficult to answer without seeing the schematic but the DC source you're using might not be putting out enough voltage to trigger a threshold for the system to work - your comment in the OP that you were getting 12 V when using the dynamo leads me to beleive a 6 V DC source isn't going to work. OR, it could be that the system is designed for use with an AC source there may be some filtering with series capacitance which would block DC if used as the source....tough to say.

About the 12 VAC in my original post: That's open circuit voltage from the dynamo, and it's very typical. AFAIK all bicycle dynamos put out fairly large voltages in open circuit mode. They function as (roughly) constant current devices, almost always delivering about half an amp. E=I*R so they show low voltage into low resistances, high voltage into high resistances, including open circuits.
With classic incandescent bulbs, the bulbs were chosen for 12 Ohms resistance at operating temperature. P=I^2*R gave 3 Watts.
That system (including the inherent self-regulation of the dynamos) was so widespread that when LED headlamps came into being, it made sense to have them work in the same system.
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- Frank Krygowski