Author Topic: Fun for nerds (Read 131556 times)

RoGeorge · « **Reply #100 on:** March 03, 2020, 07:43:12 am »

What value is that?

bsfeechannel · « **Reply #101 on:** March 03, 2020, 10:52:07 pm »

Quote from: RoGeorge on March 03, 2020, 07:43:12 am

What value is that?

I don't know, but R3 is 470Ω.

RoGeorge · « **Reply #102 on:** March 22, 2020, 05:06:41 am »

(no Catgirls anime, Mousegirls for real)

The making of Mouse computer advertising:

RoGeorge · « **Reply #103 on:** March 24, 2020, 08:12:00 pm »

RoGeorge · « **Reply #104 on:** April 09, 2020, 09:46:56 pm »

Without a Smith chart or a computer, can you do impedance matching and controlled attenuation in your head?

RoGeorge · « **Reply #105 on:** April 10, 2020, 09:12:38 am »

Terahertz Geometric Diode

https://phys.org/news/2020-04-one-way-street-electrons.html

Ratcheting quasi-ballistic electrons in silicongeometric diodes at room temperature
Science 10 Apr 2020:
Vol. 368, Issue 6487, pp. 177-180
DOI: 10.1126/science.aay8663

RoGeorge · « **Reply #106 on:** April 17, 2020, 08:45:36 pm »

Do Gods read Holy Books?

Quanta Magazine: The Computer Scientist Who Can’t Stop Telling Stories

Alphaprot · « **Reply #107 on:** April 18, 2020, 01:54:05 pm »

Yet another idiot (me!) who tried to get the password from the scripts.

RoGeorge · « **Reply #108 on:** April 20, 2020, 04:15:04 pm »

A sharpie is 15 times thinner than a human hair.

Meh, about 140 millionths of an inch (3.5\$\mu\$m).

SiliconWizard · « **Reply #109 on:** April 20, 2020, 04:23:09 pm »

Hopefully she doesn't keep this for long. I don't think that would do her ear much good.

RoGeorge · « **Reply #110 on:** April 22, 2020, 01:28:22 pm »

RoGeorge · « **Reply #111 on:** May 16, 2020, 09:16:21 pm »

A solar water pump with no moving parts

RoGeorge · « **Reply #112 on:** May 19, 2020, 08:34:32 am »

RoGeorge · « **Reply #113 on:** May 30, 2020, 09:29:38 pm »

Compared testing and choosing the proper light bulb:

RoGeorge · « **Reply #114 on:** June 05, 2020, 05:47:08 am »

RoGeorge · « **Reply #115 on:** June 07, 2020, 09:08:34 am »

Solder on Al with CuSO₄ + NaCl + FeCl₃

https://www.instructables.com/id/Solder-Electronic-Components-on-Aluminum/

Or just skip the whole procedure and solder normally, straight on aluminium, like you would do when soldering on a normal copper PCB, except for aluminium soldering you need to keep the soldering point covered in oil, so the oxigen won't reach the aluminium to form aluminium oxide. Aluminium oxide is the one that prevents the solder to stick, and it forms almost instantly in air.

Put a drop of oil on the future soldering spot, scratch a little the aluminium surface under the oil drop in order to remove the invisible oxide, then solder under the oil blob. Solder has no problem sticking on unoxidized aluminium, and the drop of oil stays in the way of atmospheric oxigen to come in contact with the aluminium at the soldering spot.

I've tried soldering under a drop of motor oil and under a drop of cooking oil, both oil worked. Soldered this way on kitchen aluminium foil and on solid aluminium radiators. It works almost as easy as it were copper. Just don't use your best soldering tool, the oil will be hard to remove from the soldering tip. Use a sacrificial tip, or cover it in Al foil for protection.

RoGeorge · « **Reply #116 on:** June 09, 2020, 09:00:15 am »

Capiţa's Pendulum

https://en.wikipedia.org/wiki/Kapitza%27s_pendulum

Pyotr Leonidovich Kapitsa or Peter Kapitza (Russian: Пётр Леонидович Капица, Romanian: Petre Capiţa), Soviet physicist, Nobel Prize in Physics (1978) https://www.nobelprize.org/prizes/physics/1978/summary/

You probably never heard of his 1/2 of the Nobel Prize in Physics ("for his basic inventions and discoveries in the area of low-temperature physics"), because he was eclipsed by the two dudes that got the other 1/2 prize that year for scratching the pigeon's poop from their antenna in order to remove radio noises, and thus discovering the Big Bang!

(Allan Penzias and Robert Woodrow Wilson "for their discovery of cosmic microwave background radiation.")