ChaoticNeutralCzech

@ChaoticNeutralCzech@feddit.de

Ich kann Deutsch erst am Niveau B2 sprechen.

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ChaoticNeutralCzech,

That’s not a huge problem. Chernobyl and Five Kilometer Island were old reactor designs, and Fukushima mostly sustained an earthquake+tsunami (it would fully succeed under better corporation oversight)

ChaoticNeutralCzech, (edited )

He only had a 150km detour. You can’t blame him for thinking “Kyjov” is the Czech spelling of “Київ” as he might not even have known the alphabet.

ChaoticNeutralCzech,

He started his journey in Zlín, 75 km from Kyjov.

In fact, the detour could be less than double that. The way to get to Kyiv from Czechia is to get on a train to Przemysl, Poland near Ukrainian borders, from where wide-gauge trains to Ukraine are available. From Zlín, a trolleybus or local train will take you 15 km to Otrokovice where direct trains to Przemysl are available. From Kyjov, the easiest way to get to the Przemysl train is 45 minutes on an express to Staré Město u Uherského Hradiště.

ChaoticNeutralCzech, (edited )

Caught my landlord reading this
Land of Big Numbers – Te Ping Chen

What do I do?

Does multiplexing a usb power cable from 2 cables into 1 impact energy efficiency?

I have two led strips used for 2x27" monitor bias lighting. Each have their own USB cables for power. These two USB cables are plugged into a 2-port wall charger for a phone. I would like to use a 2x female to 1x male adapter to join the two USB cables into one, then plug it into a much smaller 1-port USB wall charger. The...

ChaoticNeutralCzech, (edited )

The strips use 3V white LEDs, power to which is delivered via resistors or linear current regulators. Unless you see any inductors, there is no buck converter from 5 V to 3 V.

Why does this matter? Well, with resistors and linear regulators, 𝐼in (current in) pretty much equals 𝐼out (current out). So the efficiency 𝜂 = 𝑃in / 𝑃out = (𝐼 × 3 V) / (𝐼 × 5 V) = 60 %. Extra cable resistance will reduce the current, brightness and power, but still exactly 40% of power leaving the USB charger will be wasted before it gets to the LEDs.

However, I would advise against multiple, cheap USB connectors in the circuit: when moving the setup, their resistance changes somewhat and you would get blinking. The worst thing that could happen is a switch, such low voltage cannot spark over an oxide layer and eventually even small movement will blink the lights. I would get a good thick USB cable and solder it directly to one of the strips instead of whatever it came with, connecting the other with some thick wires.

So it does not matter, if you want better efficiency, use 12V (75%) or 24V strips (87%), or get just an LED array without resistors that needs a constant current driver (theoretically 100% but CC PSUs are slightly less efficient). Or make a constant current driver by fine-tuning the voltage of a PSU (by adjusting the feedback resistive divider) to 0.5-1 V above the LEDs’ voltage drop, then using an appropriate resistor to limit the current.

ChaoticNeutralCzech, (edited )

Fire hazard? Not really. The charger will not provide more than 5 V, 3.1 A or whatever its rating is. Even if the strip fails short circuit (unlikely, most LEDs blow open and there is at least a resistor in series anyway), nothing will receive more than 15 W of power. A 1m cable can safely dissipate that.

Worst case scenario, an LED fails short and its series resistor will receive over 6x its intended power (with 5 V across it instead of 2 V, and its current will increase correspondingly). It is soldered on power-dissipating flexible PCB and will probably not blow open. It will get the area somewhat hot and potentially melt the plastic in the back of the monitor while the rest of the strip keeps glowing but more dimly. Hard to tell if it could get over flammable temperatures with moderate heatsinking and only a few watts of power.

To keep safe, I would deliberately add resistance before the LED strip, using something like a 1Ω 5W resistor (or a shitty long cable). That way, the voltage drops significantly in case of a short. Also, the LEDs will run at lower-than-intended current, which prolongs their life and decreases risk of failure.

Edit: Some microwaves have a 0.8Ω 25W resistor as part of inrush, at least in 230V regions. Feel free to use that, it will happily handle a semi-short circuit. Or you know, an automotive fuse.

The safest option is replacing the whole setup with an LED strip that has no resistors (bare LEDs) and a constant current driver.

ChaoticNeutralCzech,

I am assuming the LEDs are white (blue with yellow phosphor), which always have a roughly 3V voltage drop, this is just a physical fact. Some chips like those in LED bulbs have several LEDs in series for a voltage drop of 6/9/12/15/18 V but this is not the case here.

The vast majority of 5V strips have no step-down switching power supply (aka constant current buck converter) to reduce 5 V from the power rails to 3 V, instead just driving the LEDs with a resistor in series – it drops 2 V and if it’s a 100Ω resistor (usually labeled “101”), it lets 20 mA to the LED as per Ohm’s law. In practice, multiple LEDs are often in parallel to one resistor to save cost, in which case the current divides among them.

The strip may be RGB, in which case the LED voltages are 🔴1.8 V 🟢2.4-3.0 V 🔵3 V and pretty much the same applies. There may be an external controller but it usually just uses PWM to pulse the 5V rail of each color rather than adjusting the current. Individually cntrollable LED strips have a chip driving each LED, and there is just one power rail and serial data line between them.

By the way, the resistance of the strip’s power rails may be significant. If this is the case, do this: www.youtube.com/watch?v=wCsDZK0tJvU&t=393

ChaoticNeutralCzech, (edited )

He meant watts per meter, not minute – the strips can be cut and rejoined. As for the 5 Ah, no clue.

The circumference of a monitor is more than 1 m, so a charger of 3 A at least will be necessary for each. This is why I prefer higher-voltage strips where less current is required and higher resistance is tolerable. Anyway, the power is quite high and this could cause overheating problems.

ChaoticNeutralCzech,

You’re confused. W/m means watts per meter, and the “5Ah” is probably actually 5 A, or the current you can push through the strip (limiting the length to below 2 m).

ChaoticNeutralCzech,

I used to listen to the radio and record songs on my feature phone (mono 16k 4bit samples/s).

Now !kulturgut and downloading using NewPipe (I don’t care about quality).

ChaoticNeutralCzech,

There is little or no parallax, otherwise the arc would not be circular
circle overlay

ChaoticNeutralCzech,

And then manufacturers are like:
“You can’t let an independent mechanic have this data!”

ChaoticNeutralCzech,

I thought that was the inside view…

ChaoticNeutralCzech,

What objects are there in the bottom left?

ChaoticNeutralCzech,

Those weren’t nudes of herself, just of her photoshopped on someone else’s body.

Do you think a fake bank app would ask for nudes for verification purposes?

ChaoticNeutralCzech,

Reference?

Language by Mali Benedicto Vasanserekul

ChaoticNeutralCzech,

I think those are ^1^/100 units (like pennies/cents)

ChaoticNeutralCzech,

And when he said he likes painting model buses to distract from this false campaign:

https://pbs.twimg.com/media/D8tX_hOWsAM9T5K.jpg

ChaoticNeutralCzech,

It’s a date!

ChaoticNeutralCzech,

I agree

ChaoticNeutralCzech,

As in, put the officers who tortured the prisoners on death row, and free the convicts?

Or torture more people?!

ChaoticNeutralCzech,

I would drive in silence if I could. Traffic is loud but there are key audio cues throughout (honking, tram bell, protected railroad crossings, motor rot/min for shifting gears etc.)

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