These are obviously just a manipulative lie sales practice to make you want to buy at regular price.
Shame on you.
Similarly, recurrent Internet payments that give you one year's discount, and make you put up on your calendar to call them one year later threatening to give more discounts to be as cheap as competitors or I'm out.
Electronic oscillator by Ciro Santilli 37 Updated 2025-07-16
Something where DC voltage comes in, and a periodic voltage comes out.
Video 1.
Oscillators: RC, LC, Crystal by GreatScott! (2015)
Source. Good video. Contains actual breadboard experiments on oscilloscope and circuit diagrams
Video 1.
The Scanning Electron Microscope by MaterialsScience2000 (2014)
Source. Shows operation of the microscope really well. Seems too easy, there must have been some extra setup before however. Impressed by how fast the image update, it is basically instantaneous. Produced by Prof. Dr.-Ing. Rainer Schwab from the Karlsruhe University of Applied Sciences.
Video 2.
Mosquito Eye Scanning Electron Microscope Zoom by Mathew Tizard (2005)
Source. Video description mentions is a composite video. Why can't you do it in one shot?
Gifted education by Ciro Santilli 37 Updated 2025-07-16
If school weren't bullshit, 99% of students would be in gifted education for what they truly love and are good at.
What is sad about many programs is that they are exclusivist and non scalable, selecting people some how and non scalably educating them. We need a more "here's some projects let's do them whoever can" approach to things, maybe like Google Summer of Code.
Micronation by Ciro Santilli 37 Updated 2025-07-16
Video 1.
How do you start a new country? by Jay Foreman (2021)
Source.
Discrete by Ciro Santilli 37 Updated 2025-07-16
Something that is very not continuous.
Notably studied in discrete mathematics.
TED (conference) by Ciro Santilli 37 Updated 2025-07-16
A bit like a cult.
Many speakers are good. But especially in TEDx, we've had some notorious ones:

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