If you can wait a couple weeks, AliExpress is going to be the cheapest.

eBay may be a bit more expensive, but it’s often my go-to because you can find everything and usually there are options with short shipping times.

For not too obscure parts, I would look at Reichelt, their prices are surprisingly low (especially if you bundle your orders to save on shipping costs).

HiPER Calc Pro. A great scientific calculator I use constantly. (There is also a unpaid, ad-supported version, and the ads weren’t too intrusive the last time I tried it)

That’s probably not a bad idea, although I doubt it will make much of a difference. But since you’re redesigning the whole thing, might as well do it.

It looks like you would want an even airflow through the whole PSU. The main heat-generating components are using the sides of the housing as a heat sink. I’m guessing the fan is mostly so the air inside the housing doesn’t get too warm, not to cool individual components.

Where is the original air exhaust? If it’s near the bottom of the picture, that would confirm my theory. In that case, I would keep the fan placement as close to original as possible (i.e. the blue square).

You can use a boost converter to boost the 5V of an USB port to the 19V your notebook needs.

Assuming 5A output from a powerbank (which is probably about the max you will get without USB PD), you could theoretically get 0.55A at 19V. With the unavoidable inefficiencies, you will get less.

So, maybe enough to very slowly charge your notebook while it’s off. But when it’s turned on, the battery charge will still drop.

From a cursory read of the datasheet, using the “dead time control” pin seems to be the way to go. Basically, this pin is used to set the voltage, while the error amplifier inputs (that’s the closest function to “over current protection” this chip has) are used to adjust the output according to the load. For your application, you probably don’t need to use them at all.

My instinct would be to disable the error amplifiers by connecting pins 1,2,15 and 16 to GND. You can then connect the wiper pin of the potentiometer to the deadtime control input, with the other pins of the potentiometer connected to GND and 3.3 V.

I haven’t worked with this chip before, so take this with a grain of salt. You should probably use a simulation tool to check the circuit before you start destroying chips.

A small pair of vernier calipers. I don’t use them a lot, but sometimes they come in very handy.

You can host a Firefox sync server yourself. You could run that on something like a Raspberry Pi in your local network. If you need remote access, use something like cloudflare tunnels (although I guess that’s something else to be paranoid about).

I’m guessing it’s about documenting the assembly of safety-critical components. If some part of, let’s say an airplane fails because a bolt comes loose, the manufacturer wants to have a paper trail attached to it to prove that this specific bolt was indeed torqued to the correct spec. Connecting the wrench to the network could make this documentation much easier.

It’s called HDR (High Dynamic Range) photography. Your phone is taking three pictures: one at a medium exposure, one at a bit higher exposure and one at a bit lower exposure.

The higher exposed picture will have a blown-out sky, but more detail in the darker area, while the lower-exposed one will have a correctly exposed sky with the darker areas underexposed.

These pictures are then combined by taking the correctly exposed areas of each picture, i.e. the sky from the low-exposure picture and the shadows from the high-exposure one, giving you a single picture without over- or underexposed areas.

I don’t know about OpenCamera, but you should be able to select the size of the exposure bracket, meaning how much higher or lower the different pictures are exposed.

Alles trägt zum Klimawandel bei, die Frage ist nur wie viel. Ich fände eine einheitliche Kennzeichnung, wie groß die Auswirkung ist, sinnvoller - so ähnlich wie der Nutri-Score.

Das hätte eine tatsächliche Informations-Funktion statt dieser generellen Schuldzuweisung (“Alle Fleischesser sind böse”), die wahrscheinlich nur begrenzt effektiv wäre.

Those adapters should definitely be fine for 24 V. Running the fans off 19 V will probably work, but they will run at slightly slower RPM (probably not a big problem for a filter).

One of my monitors has had a couple of dead pixels for a couple of years. I still find myself wondering sometimes if that dark spot is part of the image or just my crappy screen.

3

Incandescent oven bulbs will probably not be replaced, simply because there is no reason for it. The “wasted” energy from an incandescent bulb is expelled as heat, and extra heat in an oven is not a problem. You can describe the bulb in an oven as a tiny heater that just happens to give off a bit of light.

As a young child, I had a wooden board with a bunch of different light switches mounted to it. Nothing to tinker with, but I had a lot of fun with the physical sensation of switching them on and off. I think that’s all you can really ask for at that age.

Later on, I enjoyed taking the switches apart, figuring out how they work and using them in my electronics projects.

My point is, whatever you choose should be physically fun, even without understanding it. A few switches and maybe a blinking light can entertain a toddler for a long time. The tinkering can come later.