ChaoticNeutralCzech

in European

Oh yes, my favourite language. It's "vzduch" or similar in most Slavic languages, and I'd bet you're not pronouncing it right.

It's the circuitry that burns out, and many of these filament-style LED lights literally only have a resistor as their main component.

Not true. I've been dumpster-diving for LED bulbs for 5 years and in the majority of cases, it's one LED in a series chain that burns out (fails open circuit). As for the circuitry, the most common failure point is the inductor between the capacitors smoothing out the rectified mains voltage.

Mains filament bulbs with nothing but a resistor exist but they flicker between 0 and 100% at 100 or 120 Hz, which is not very pleasant. Good filament ones have circuitry very similar to the plastic ones. The reason filament bulbs last longer is better heat dissipation from the LEDs, and the circuitry does not get too hot either.

No, shorting a dead LED in a series chain of 10-20 will NOT burn your house down, it's barely a difference to the driving circuit. Unless you're buying knockoffs, there is a fuse in the base that will blow at like 0.5 A, no matter what you do to the circuitry. However, the other chips will likely not last much longer than the first dead one (unless you dooby the bulb, see below), so it's not worth doing, and a poorly reattached plastic globe can come off and expose mains voltage. If all chips are OK, you can cut it open to check the inductor between smoothing capacitors and replace it if it has failed open circuit, or short it if you accept a little extra flicker and/or electrical noise.

I've seen power supply boards of LED bulbs that literally burned themselves down to the crisp (never in ones that I modded) but the housing contained the fire thanks to its heat-dissipating design.

In many bulbs, you can adjust the value of a current-sensing resistor (usually one or two in parallel, about 2-30 Ω) to make your own "Dooby" lamp with lower power and way longer life. Of course, you need to know something about electronics.

What can burn your house down is still using incandescent and halogen bulbs. You may lay a piece of paper on top of a lamp and it can fall in when moved by the hot air, touching the bulb...

They are probably very low-power and don't get hot, which would kill them faster.

I have been dumpster-diving for LED bulbs for 5 years. None of them had 200 chips, they usually have about 5-30 packages with 1-6 diodes each for a total of around 30-60 so that they total some 90-180 V in series (I live in a 230V mains region, and the 330V rectified mains can be efficiently transformed to that voltage by an SMPS). Because they are in series, if one in the series chain fails open circuit (the most common way), the entire chain goes out. Yes, fixtures (not bulbs) with 100+ LED chips exist and if they are designed to operate at a low voltage with all chips in parallel, the failure of one will not affect the others.

There are lots of effects you cannot explain without air. Even if you haven't been to school, you can observe wind, use a hairdryer, blow up balloons, fly a drone etc.

It is not. Both gases and liquids are fluids, though.

It's easier to take precautions though. You probably don't have an insulated USB port or throwaway host device but handling QR codes safely just takes basic tech and skill.

Important advice:

• Don't use apps that auto-open URLs in QR codes when pointed at!
• Make sure the app shows the full content of the QR code and lets you peruse it indefinitely before you open the link!
• Know the structure of URLs and common pitfalls!

Recommendations:

• Be extra suspicious if there is no URL printed next to the code, or if the printed URL is different.
• Use an open source reader app (most QR codes don't contain secrets but it's got permission to use either camera!) that does not resolve Punycode (Unicode in TLDs).
• Strip any tracking parameters you spot before following any URLs.
• Be careful if the QR code could have been easily tampered with (on a sticker over the original one, or on a plain sheet of paper inserted into a plastic wrap together with the rest)

I think today's generation's equivalent is free Wi-Fi networks. Kids without mobile data in an area without an established public network will connect to just about any open one unless the SSID includes "LaserJet" or similar.

Has been taken down. See archived copy

Has been taken down. See archived copy

I'm adding it to my collection

The use of an identical master/slave connector and 12V power were forward-thinking too, too bad most portable electronics back then only accepted 5 V. It even had a non-HD but standardized video interface (DV,) way before MHL and eventually USB-C. I would also prefer daisy-chaining to hubs but not all devices had two ports.