Ciro Santilli is a fan of this late 2010's buzzword.
It basically came about because of the endless stream of useless software startups made since the 2000's by one or two people with no investments with the continued increase in computers and Internet speeds until the great wall was reached.
Deep tech means not one of those. More specifically, it means technologies that require significant investment in expensive materials and laboratory equipment to progress, such as molecular biology technologies and quantum computing.
And it basically comes down to technologies that wrestle with the fundamental laws of physics rather than software data wrangling.
Computers are of course limited by the laws of physics, but those are much hidden by several layers of indirection.
Full visibility, and full control, make computer tasks be tasks that eventually always work out more or less as expected.
The same does not hold true when real Physics is involved.
Physics is brutal.
To start with, you can't even see your system very clearly, and often doing so requires altering its behaviour.
For example, in molecular biology, most great discoveries are made after some new technique is made to be able to observe smaller things.
But you often have to kill your cells to make those observations, which makes it very hard to understand how they work dynamically.
What we would really want would be to track every single protein as it goes about inside the cell. But that is likely an impossible dream.
The same for the brain. If we had observations of every neuron, how long would it take to understand it? Not long, people are really good at reverse engineering things when there is enough information available to do so, see also science is the reverse engineering of nature.
Then, even when you start to see the system, you might have a very hard time controlling it, because it is so fragile. This is basically the case of quantum computing in 2020.
It is for those reasons that deep tech is so exciting.
The next big things will come from deep tech. Failure is always a possibility, and you can't know before you try.
But that's also why its so fun to dare.
Stuff that Ciro Santilli considers "deep tech" as of 2020:
- brain-computer interface
- fusion power. The question there is, when is "deep", "too deep"?
Applicaitons of power, we have to remember it is there to notice how awesome it is!
- lightning
- motors
- sending nad receiving communication signals
- computers, which in turn can do computations and improved communication
Most promising approaches as of 2020:
- Joint European Torus
- General Fusion: compress with liquid metal. Intends to demo in JET site.
- Helion Energy: direct fusion to electricity conversion without steam, direct from magnetic field movements
- First Light: shoot microscopic objct at a target to crush it so much that fusion happens
Once again, relies on superconductivity to reach insane magnetic fields. Superconductivity is just so important.
Ciro Santilli saw a good presentation about it once circa 2020, it seems that the main difficulty of the time was turbulence messing things up. They have some nice simulations with cross section pictures e.g. at: www.eurekalert.org/news-releases/937941.
Operated by a hand crank.
Positive center is way more popular: gearspace.com/board/electronic-music-instruments-and-electronic-music-production/1222518-center-negative-vs-center-positive-power-supply.html
This notation is designed to be relatively easy to write. This is achieved by not drawing ultra complex ASCII art boxes of every component. It would be slightly more readable if we did that, but prioritizing the writer here.
Two wires are only joined if
but the following are:
+
is given. E.g. the following two wires are not joined:
|
--|--
|
|
--+--
|
Simple symmetric components:
-
,+
and|
: wireAC
: AC source. Parameters:e.g.:Hz
: frequencyV
: peak voltage
If only one side is given, the other is assumed to be at a groundAC_1Hz_2V
G
.C
: capacitorG
: ground. Often used together withDC
, e.g.:means applying a voltage of 10 V across a 10 Ohm resistor, which would lead to a current of 1 ADC_10---R_10---G
L
: inductorMICROPHONE
. As a multi-letter symmetric component, you can connect the two wires anywhere, e.g.or:---MICROPHONE---
| MICROPHONE |
SPEAKER
R
: resistorSQUID
: SQUID deviceX
: Josephson junction
Asymmetric components have multiple letters indicating different ports. The capital letter indicates the device, and lower case letters the ports. The wires then go into the ports:
D
: diodeSample usage in a circuit:a
: anode (where electrons can come in from)c
: cathode
Can also be used vertically like aany other circuit:--aDc--
We can also change the port order, the device is still the same due to capital| a D c |
D
:--cDa-- | Dac-- | Dca-- | --caD
DC
DC source. Ports:E.g. a 10 V source with a 10 Ohm resistor would be:p
: positiven
: negative
If only one side is given, the other is assumed to be at a the ground+---pDC_10_n---+ | | +----R_10------+
G
. We can also omitp
andm
in that case and assume thatp
is the one used, e.g. the above would be equivalent to:If the voltage is not given, it is assumed to be a potentiometer.DC_10---R_10---G
T
: transistor. The ports aresgTd
:Sample usage in a circuit:s
: sourceg
: gated
: gate
All the following are also equivalent:---+ | --sgTd--
| g --sTd-- | --Tsgd-- |
I
: electric current source. Ports:s
: electron sourced
: electron destination
V
: Voltmeter. Ports:If we don't need to specify explicit positive and negative sides, we can just use:p
: positiven
: negative
without any ports. This is notably often the case for AC circuits.---V---
Optionaly, we can also add the sides as in:
Numbers characterizing components are put just next to each component with an underscore. When there is only one parameter, standard units are assumed, e.g.:
means:Micro is denoted as
+-----+
| |
C_1p R_2k
| |
+-----+
- a capacitor with 1 pico Faraday
- a resistor with 2 k Ohms
u
.Wires can just freely come in and out of specs of a component, they are then just connected to the component, e.g.:
means applying a voltage of 10 V across a 10 Ohm resistor, which would lead to a current of 1 A
DC_10---R_10---G
Main implementations: the same as electronic switches: vacuum tubes in the past, and transistors in the second half of the 20th century.
The fundamental intuition about capacitors is that they never let electrons through.
They can only absorb electrons up to a certain point, but then the pushback becomes too strong, and current stops.
Therefore, they cannot conduct direct current long term.
For alternating current however, things are different, because in alternating current, electrons are just jiggling back and forward a little bit around a center point. So you can send alternating current power across a capacitor.
The key equation that relates Voltage to electric current in the capacitor is:
So if a voltage Heavyside step function is applied what happens is:More realistically, one may consider the behaviour or the series RC circuit to see what happens without infinities when a capacitor is involved as in the step response of the series RC circuit.
- the capacitor fills up instantly with an infinite current
- the current then stops instantly
Ideally can be thought of as a one-way ticket gate that only lets electrons go in one direction with zero resistance! Real devices do have imperfections however, so there is some resistance.
First they were made out of vacuum tubes, but later semiconductor diodes were invented and became much more widespread.
- youtu.be/Fwj_d3uO5g8?t=153 how it works
- youtu.be/Fwj_d3uO5g8?t=514 applications:
- protection against accidental battery inversion
- rectifiers, notably mentions a diode bridge
GPIO generally only supports discrete outputs.
But for some types of hardware, like LEDs and some motors, the system has some inertia, and if you switch on and off fast enough, you get a result similar to having an intermediate voltage.
So with pulse width modulation we can fake analog output from digital output in a good enough manner.
Notably used to connect:
- pin headers
- breadboard holes
You can buy large sets of them in combitation of male/male, male/female, female/female. Male/male is perhaps the most important
These often come pre-soldered on devboards, e.g. and allow for easy access to GPIO pins. E.g. they're present on the Raspberry Pi 2.
Why would someone ever sell a devboard without them pre-soldered!
Allows you to connect two adjacent pins of a pin header. Sometimes used as a hardware configuration interface!
Something where DC voltage comes in, and a periodic voltage comes out.
- youtu.be/eYVOdlK15Og?t=66 RC oscillator on breadboard. Produces rectangular wave. Mentions popular integrated circuit that does it: 555 timer IC.
- youtu.be/eYVOdlK15Og?t=175 LC oscillators allows for higher frequencies. Produces sinusoidal output on MHz range. Uses an amplifier to feed back into input and maintain same voltage. Hard to make reliably on breadboard.
- youtu.be/eYVOdlK15Og?t=315 crystal oscillator. Mentions it acts like an LC oscillators. Shows and equivalent model. Wish he had talked more about them. You need support components around it: similarly to the LC case, the amplifier is generally not packaged in.
Oscillator made of an LC circuit.
It resists to change in electric current. Well seen at: Video "LC circuit by Eugene Khutoryansky (2016)".
Although transistors were revolutionary, it is fun to note that they were just "way cheaper and more reliable and smaller" versions of exactly the main functions that a vacuum tube could achieve
People had already patented a lot of stuff before without being able to make them work. Nonsense.
As the name suggests, this is not very sturdy, and was quickly replaced by bipolar junction transistor.
By William Shockley in 1948 also at Bell Labs Murray Hill.
As of 2020, not used anymore in logic gates, but still used in amplifiers.
By Andy Haas, an experimental particle physics professor: as.nyu.edu/content/nyu-as/as/faculty/andy-haas.html What an awesome dude!
899 USD as of 2022, takes a year to ship as they gather up a lot of orders before producing.
Sounds so cool, especially the multi functionality. Shame so expensive.
They do seem to have been very innovative, and have had a very good work culture. They also had a huge impact on the Silicon Valley startup scene.
Some products they are known for:
- oscilloscopes
- Atomic clocks, notably highly portable ones, see e.g. Video "Inside the HP 5061A Cesium Clock by CuriousMarc (2020)"
- pocket calculator
In a way, Agilent represents the most grassroots electronics parts of HP from before they became overly invested in laptops and fell.
They spun out the electronics part as Keysight in 2014, becoming life science only.