I am always tweaking this blog. Unfortunately I tend to edit existing posts, so it is worth re-checking pages you are interested in, if you have visited before.
- Some History of technology
- Shakespeare Scrapbook
- 80 years of BBC TV
- TTL & Microprocessors
- Sallen & Key slope
- Rare pigs
- Flying Scotsman
- Ancient civilisations mystery
- Mystery of the Princes in the Tower
- Aviation mysteries
- The Maks
- Renaissance to Rock
- Raspberry Pi Part 2
- Simple Twin T oscillator
- MR16 Led bulb problem
- Darlington Pt 3 Serendipity
- Hi fi humour
- Cost effective darlington amp Part 2
- Raspberry Pi
- Metal dome tweeters
- Orwell festival
- My new amplifier
- active and passive elliptic crossover
- Car & plane concepts
- Warnock’s dilemma
- simple cost effective darlington amplifier
- overclocking the 555 timer
- Rhythm of the rails
- Mission Freedom & AR48LS
- 741 and inventions
- Fixing the 42PF7520D
- Pioneer Powerbass
- 3rd order low pass filter table
- X-max problems?
- Tweaking the DAP D3109
- LS3/5A Inspiration
- Homage to Tannoy
- W6-1139 & TM1A compact 3 way design
- Tweaking the Mission 762
- Loudspeaker projects
Where it began, for our purposes, little known Elizabethan physician Gilbert
Thought Morse invented the Telegraph? Francis Ronalds invented it in 1816. Unfortunately no-one wanted it.
It has been 150 years since Maxwell presented his equations:
The history of Maxwells equations
My friend has summarised them here:
Heaviside’s conflict with Preece “Theory versus practice”
A worthy biography of Heaviside is “Oliver Heaviside” by Paul Nahin
Another 150th anniversary George Boole. Boole like Heaviside was self -taught.
There is more to Boole than Boolean
Interesting article about a contemporary of Maxwell and Boole, namely Babbage
More detail on the invention
Article about Babbages friend, the first programmer, Ada
Great piece on Ada and Babbage by Wolfram
Another contemporary British invention, the Bessemer process
A quartet of Victorian engineers beginning with B
I had to make it a quintet of people beginning with B. Thomas Bayes came up with Bayes’ Theorem, a basic law of probability governing how to modify one’s beliefs when new evidence arrives. Are you Bayesian or Boolean?
In the Boolean worldview, the world is organised into basic situations such as Sydney being north of Melbourne. Such situations are facts. Truth is correspondence to facts. That is, if a belief matches a fact, it is objectively true; if not, it is objectively false. If you and I disagree, one of us must be right, the other wrong; and if I know I’m right, then I know you’re wrong. Totally wrong.
In the Bayesian worldview, beliefs are not simply true or false, but more or less probable. That is, we can be more or less confident that they are true, given how they relate to our other beliefs and how confident we are in them. If you and I disagree about the cause of climate change, it is not a matter of me being wholly right and you being wholly wrong, but about the differing levels of confidence we have in a range of hypotheses. Dare I say it, shades of grey!
Good explantion of Bayes Theorem
Another question, are you Babylonian or Balkan in your Philosophy? Feynman used to say that there were two kinds of Physicists, the Babylonians and the Greeks. He was referring to the opposing philosophies of those ancient civilizations. The Babylonians made western civilization’s first great strides in understanding numbers and equations, and in geometry.
Yet it was the later Greeks – in particular Thales, Pythagoras, and Euclid – whom we credit with inventing Mathematics. This is because the Babylonians cared only whether or not a method of calculation worked – that is, adequately described a real physical situation – and not whether it was exact, or fitted into any greater logical system. Thales and his Greek followers, on the other hand, invented the idea of theorem and proof – and required that for a statement to be considered thorough, it had to be an exact logical consequence of a system of explicitly stated axioms or assumptions. To put it simply, the Babylonians focused on phenomena, the Greeks on the underlying order.”
Nevertheless, the existence of Babylonian method has actually a deep sense: axiomatic approach can be formulated only if satisfactory number of facts, needed for the generalization, is accumulated.
Interesting reflections on Feynman:
Comments on the Feynman minority report of the shuttle disaster, interesting blog BTW
How ARM happened
More on the history of ARM
Arm 25th anniversary
350 years of scientific publishing. The Royal Society
Contemporary work showing interest in Science from the nobility
A good summary of the basics of electronics:
Germanium is making a comeback:
The hacker hacked
The history of spreadsheets or the first killer app:
Unsung computing hero Douglas Englebart
The engineering approach to innovation in science
Review of TRIZ for dummies
How to engineer serendipity
Divisions of time
Talking astronomy, where Jocelyn Bell discovered the Quasar. She, Lise Meitner and Rosalind Franklin are more famous female scientists than if they were Nobel Laureates:
Talking of Rosalind Franklin here is the story of the how the structure of DNA was discovered:
Lest I be accused of eurocentrism in the history of science
Sorry its creeping back in. Horrocks
Restoring the balance, Martin Bernal and Black Athena
More balance, Sanskrit and the periodic table
Erdos and the Egyptian fraction problem:
Computers can lead to experiments not being repeatable:
The future of the professions
Philosophy and work/life balance
Lord Nuffields philanthropy
Babylonian maths more advanced than we previously thought:
On the other hand:
The clock on most computers started theoretically on 1st Jan 1970. Someone has worked out when the clock on the Anti-Kythera mechanism started, for solar eclipses it is 12 May 205BC.
The age of enlightenment has become the age of entanglement
Newtons recipe for the Philosophers stone
The extraordinary career of William Dampier
Richard Hakluyt and his early travel book
The silicon revolution started at Shockley Semiconductor in April 1956 at Santa Clara which was the year Shockley got the Nobel prize for Physics for inventing the transistor. However by 1957 a number of staff he had recruited left to join Fairchild. More here:
How Silicon Valley got the name in 1971:
Unfortunately, all those manufacturing plants in Silicon Valley have left a toxic legacy in the groundwater.
The is/ ought problem
The above was written by Enlightenment philosopher David Hume who may have got some of his ideas from Buddism
Salvation by algorithm!
A scientific look at religon
Smartphones and social media are supposed to connect us. What happens when we are so constantly connected that forget how to be alone?
How information technology affects capitalism:
Another alliterative professor (see 741) was Ephraim Everitt who came up with the radical idea that Shakespeare had written more plays and suggested some. His idea was pooh-poohed at the time but these days there is more of an academic consensus that the bard wrote Edward III. Everitt also reckoned that the manuscript of Edmund Ironside was in Shakespeare’s own hand.
Well this is interesting. Kims FFP technique produced the following table:
Which shows Edward III to be more like Marlowe than Shakespeare. Also interesting is that the Henry VI part 2 and 3 plays are grouped with Marlowe, possible collaboration when they were both working for Stanley, but part 1 is elsewhere, possibly Nashe had some involvement. Dido, Queen of Carthage is also in the same area, might Shakespeare be the collaborator with Marlowe back in 1587. So keen is Shakespeare on the story of Dido, the Queen of Carthage, that he mentions her four times in The Tempest, twice in Titus Andronicus, and once each in The Merchant of Venice, 2 Henry VI, Antony and Cleopatra, Hamlet, and Romeo and Juliet.
One issue I have with Kims FFP technique is the spelling or lack of consistency in Shakespeares time:
Co-author with Marlowe of Henry VI ?
Another play to add to the canon?
Amazing what people can derive from a few lines of Shakespeare
Shakespeare as it would have been pronounced in 1600
Translate your text to Shakespearean dialogue!
Cumberbatch does Hamlet
Not a lot of people know that Shakespeare translated Hamlet from the original Klingon. For too long, readers throughout the Federation have been exposed to The Tragedy of Khamlet, Son of the Emperor of Qo’nos, that classic work of Klingon™ literature, only through inadequate and misleading English translations. Now at last, thanks to the tireless efforts of the Klingon Language Institute, this powerful drama by the legendary Klingon playwright, Wil’yam Shex’pir, can be appreciated in the elegance and glory of its original tongue.
Talking Sci-Fi I realised I had just missed towel day:
I have an obscure connection with Douglas Adams and it’s not that I once drove a Ford Prefect! There is a related obscure connection between Adams and the renaissance in that Douglas lived in the same small village as William Byrd, the medieval composer.
Consorts conjectures The absence of information about the ‘lost years’ of the Bard has led me to make some informed guesses about those lost years.
1578 Shakespeare leaves school early due to his father’s financial downfall and becomes teaching assistant at a noble house. He develops playwriting and acting skills teaching children. The noble house could have been the Stanley family place at Lathom. I think he could have developed into Stanleys Poet as it was fashionable then for noble people to have your own tame poet. When Stanley formed his own acting troupe in 1587 Shakespeare would have been in a good position to join the troupe. Stanley was a lawyer and he might have doubled as Stanleys scrivener..
1582 Aged 18, he marries Anne Hathaway and they have a child (this is known)
1585 After his twins are born moves to London. Possibly with Stanley at his London base (Cannon Row).
1587 He becomes so useful to acting company that he is invited to join, writing plays from scratch.
One more alliterative professor Hildegard Hammerschmidt-Hummel and Shakespeares portraits
A history channel documentary covered this (50 mins in)
Modern re-creation of Shakespeares portrait
The lack of evidence of Shakespeares life has led to some notorious forgeries:
These are extensively covered by yet another alliterative Professor, Samuel Schoenbaum’s in Shakespeares lives. Schoenbaum dominated Shakespeares studies and was intolerant of others views, yet with so little factual evidence there is only speculation. Ian Wilson in “Shakespeare the evidence” has a convincing argument that Shakespeare was under the patronage of Ferdinando Stanley.
The worldwide following of Shakespeare
Another attempt to rewrite the Bard
Where did Shakespearean Londoners go when they wanted a day out? To Brentford Staines or Ware according to Middleton and Dekkers Roaring girl of 1612. In Jacobean times the Thames was tidal up to Staines, so they would go up river on a flood tide and back downriver on an ebb tide. The journey to Ware was more difficult up the River Lea. Edmund Spenser described the river in his epic poem The Faerie Queene as “the wanton Lea that oft doth lose his way”. The Lea could confuse travellers with its twisting, splitting course.
Parody of “Shall I compare thee to a summers day”
Discussing memorable Shakespeare lines with a friend and he remembered “What news on the Rialto” from the Merchant of Venice. This had resonances with me as I am restoring a Reliant Rialto car! Another line from the same play he remembered was “Do cream and mantle like a standing pond”
The poisons, potions and charms of Shakespeare
On the 400th anniversary this seems apposite:
Which is Shakespeares most popular play:
Interesting that King Lear does not appear in the top ten in the US but is popular in the UK, perhaps we have more ageing thespians.
There is a link between the rythym of Rap music and iambic pentameter which I have only just realised, thanks to Lenny Henry.
Restoration of Religious paintings John Shakespeare supposedly whitewashed
Not alliterative but Oxford professors CS Lewis, Tolkien and Lewis Carroll turned Christianity, Anglo Saxon and mathematics into successful works of fiction.
Cornish influence on medieval Theatre:
On Nov 2 1936 the BBC started TV broadcasts from Alexandra Palace. There were 2 systems the Baird and the Marconi-EMI and both systems were tried, the Marconi system winning. That decision was made in March 1937. On May 12th 1937 the first British outside broadcast was made, the Coronation of George VI. You could buy these sets at launch:
By September 1938 KB and Philips sets were also available
These were household names back until the 1980’s, when Sony, Hitachi (GEC) Toshiba(Rank), Panasonic, Sanyo(Philips/Pye) and Tatung (Decca) took over. The bracketed make is the factory that the Japanese took over. Pedants will point out that Tatung was from Taiwan. Funny how the Japanese made a success of TV production in the UK when the Brits could not.
A BBC programme covers the start up:
The Baird work was not wasted as the flying spot Telecine became a useful piece of kit.
The 1953 coronation of the present Queen provided a major boost for TV. A lot of the population finding a place to view a TV set. My father in law built a DIY one for the occasion.
TTL (that is transistor – transistor logic) is 50 years old
Good article on the history of TTL
A 4bit microprocessor built in TTL
An even simpler TTL processor
A more complex TTL microprocessor
A TTL processor that does not use the 74181 ALU also interesting web-ring
Not a lot of people remember the Signetics 8200 series and the AMD 9300 series TTL
While I am on a historical bent, this site is good on old microprocessors etc.
The z80 versus the 6502
The development of the 6502
and this on the 70s and 80s personal computer boom
Historical computer designs index
The modern way of designing a microprocessor using VHDL
People still use DOS
The 16 bit (2 byte) microprocessor came out in the mid seventies
I have not been paying attention to what can be squeezed into the humble 8 pin DIL package. How about the NXP LPC810M, a 32 bit ARM microcontroller or the Microchip 128K X 8 serial SRAM? Are they the most complex chips put in the package?
There has been a renaissance in beer brewing in the UK and US. I think it started with the Campaign for real ale (CAMRA) in the UK and spread to the US where it is called craft beer. Dissatisfaction with the products of the large breweries in each country started the trend. With 1400 breweries in the UK and about 4200 in the US it has taken off.
I recently found the best brown ale, Lewes Castle Brown by Harvey’s of Sussex. I must go and see the Widmer Bros Brewery in Portland, Oregon since it combines 2 of my interests beer and trains.
Maybe us Brits know something about beer
Beer and a statistics pioneer
Reddit beer forum
I am only going out for one
This guy likes beer
The humble unity gain Sallen and Key filter can be versatile. Don Lancaster’s Active filter cookbook showed me some of the filter shapes you could get. By varying the damping you can get upward and downward slopes to the frequency response . A nice article by Kenneth Kuhn showed me how to calculate the component values given the damping and the frequency.
At step 4, here is where I deviate from the above by using this website
Enter the capacitor values and it will compute R1 and R2 as 6.2k and 18K respectively, as per Kuhn’s analysis. Here is a Ltspice analysis of the circuit showing the 6dB peak of the underdamped case, even though the op-amp is configured as unity gain! By swapping the capacitors we get an overdamped case.
Or you could use a Quad style tilt equaliser, if your overall system has a problem.
Very nice article by the late great Chu Moy on headphone equalisers including the tilt type
Talking of headphones, Bose Qc35
Back to Sallen and Key. an interesting analysis: