Electronics

The book I read to research this post was Electronics Made Simple by Henry Jacobowitz which is a very good book that I bought from a car boot sale. This book was published in 1982 so is quite old. It’s around 280 pages so is a decent length. It also contains lots of graphs of the characteristics of components on an oscilloscope which are mostly partly dependent on its rating. I thought these were quite useful. Of course since 1982 there have been huge developments including components shrunk on a minute scale. A diode is simply a component with an anode and cathode and the voltage is kept constant. There are triodes, tetrodes and pentodes with various numbers of anodes and cathodes and these can reduce the voltage. Trtrodes and pentodes can have shielding on the outside to form capacitors. A capacitor stores electricity for a brief period.You can have switches that often have gas in side and 2  apart contacts that can close or open depending on what you need. Magnetism is often used to close these. You can have mercury filled ones for a heavy duty rectifier. A rectifier changes AC current to DC current normally. In electronics there is also radio waves that travel at the speed of light and bounce off the ozone layer in the atmosphere and reflect a signal back to earth but a long way away. I did enjoy reading this book and do recommend it.

A Brief History Of Time

The book I read to research this post was A Brief History Of Time by Stephen Hawking which is a very good book that I bought from a car boot sale. This book is around 230 pages so is a decent length. A film recently was made about Stephen’s life and Eddie Redmayne won the Oscar for Best Actor for his portrayal. He is probably the greatest physicist of his generation and this book is his defining text. He explains a lot of complex concepts like the string theories and blackholes in language you can mostly understand. He did have a progressive debilitating illness for most of his life and many people regard him as almost as great as Einstein and Newton. I did very much enjoy this book and definitely recommend it. The subject Stephen specializes in is blackholes where if a star has more than a certain critical mass it eventually collapses and becomes one. A star like our sun will become a red giant then a white dwarf. The sun is less than that critical mass. Stars like Cygnus X-1 has got a nearby black hole and is 6 times bigger than our sun.

The History and Practice Of The Art Of Photography

The book I read to research this post was The History and Practice of The Art Of Photography by Henry Hunt Snelling which is a very good book that I downloaded for nothing from kindle. This book was published in 1849 and is a history of what was then a recent discovery invented in 1827 by Niepce. It was a British invention like a lot of things in that era. I think this book is quite a classic probable a bit less applicable to our world of technology but never the less interesting. It was known to the early alchemists that light reacted with silver compounds that made it go lighter or darker which is what photography is based on. In this book he uses things like bromide paper and silver chloride with the basic principles being that forms of bleach are added that only react with the silver compound when light is present making it lighter in those areas. Initially photography was thought to be useful for photographing the sun. Later Samuel Morse the inventor of morse code saw an application in doing portraits. Of dark places at this time photography was still useless and people like historians sometimes still had to draw things like antiquities in dark places. This book is 78 pages and there is information on the old methods of developing and taking photos. I think there is still something called a Camera Obscura in the Welsh seaside town of Aberystwyth which is quite a tourist attraction and is a room that is also a giant pinhole camera. People go into the room and can see an inverted scenic view of outside projected on a wall. It is made dark and light comes through a small hole achieving this effect. I very much enjoyed reading this book and would definitely recommend it.

Programmable Logic Controllers

The book I read to research this post was Programmable Logic Controllers by W Bolton which is a very good book that I bought from a car boot sale. This book was published in 2004 so as a result covers mostly legacy hardware. It is 240 pages so is fairly long. Programmable Logic Controllers are often called PLC’s for short and in the present day it would be CAM or computer aided manufacturing using a language like LISP or Python and maybe something like an Arduino controlling the process. This book uses logic gates with commands like AND, OR and NOT. It would be negative or positive according to conditional inputs. These often have to be programmed in Machine Code using either binary or hexadecimal to represent various commands. Nowadays most kit electronics are going open standard so they can be bought from various manufacturers and you know they will work together. This book does look at components like photo-resisters that are light dependent, reed switches where a magnetic current opens or closes a circuit and also bimetallic switches made with a brass and copper strips joined together so that as they expand unevenly with temperature. The brass expands more than the copper so it bends and touches a contact opening or closing a circuit. These are only a small amount of the components covered. Obviously a lot of the same components are still used for various purposes and this book is of interest in covering this. I bought this book for 50p and would say if you see it for sale somewhere at a low price it may be a worthwhile purchase. I do recommend it.

The Speed Of Mass

The book I read to research this post was The Speed Of Mass by Philip J Morgan which is a very good book that I read at kindle unlimited. This book is about the various theories in physics, many of which are conflicting and tries to make sense of it. The book is by a non-mathematician which makes it a book we can understand. It’s also written in a straightforward manner and mostly looks at some of the experiments carried out and there implications from the results. It is only around 60 pages so is quite short. The first chapter is probably the most interesting. In this a particle called a muon with a lifespan of 2.2 micro-seconds before it becomes an electron and 2 neutrinos and travels at 99.94 % the speed of light was checked to see how far it would travel in 2.2 micro-seconds. It was fired around a 15 km particle collider. In theory it should do 40 laps but don’t forget when something gets to the speed of light time slows down locally. In fact it did about 400 laps raising hopes that maybe if we can build space-ships able to go that fast maybe there is hope for them reaching the nearest stars. Einstein of course in the Theory of Relativity came up with the idea that as something travels at faster and faster velocity time gradually slows down. In theory the fastest something can travel through a vacuum is the speed of light. After that time stops. This is an interesting book that I enjoyed and do recommend.

 

Signals and Systems

The book I read to research this post was Signals and Systems For Dummies by Mark Wickert which is quite a good book which I bought from kindle. I might be being a bit unfair on this book as in the intro it says you need knowledge of engineering and things like calculus to understand this book. I probably am not knowledgeable enough on these topics so most of it I didn’t understand. What I did understand was interesting though. From what I understand of calculus the basic principle is x and y are related but variable amounts and you are given an equation which shows this. You draw a graph to show when x equals one amount, y equals another and this can be over an infinite scale. When you look at things like voltage and current you can see a similar relationship although it is quite a simple one. Some interesting things it says in the book are if you have 2 amplifiers set to the same frequency, they will cancel each other out. Also if you do a pop concert you may need a linear amplifier to take the vocals and music and broadcast it together without distortion. Of course some pop groups want distortion so use a non-linear amplifier. Another interesting thing is if you are doing a course in signals and systems, maybe as part of electrical engineering and it leads to an exam, there will normally be a few easy questions and it is a good idea to read the paper through and answer these questions first & it’s amazing how many students over look this. I think this book is for students doing something like applied maths or physics and I am sure it would help them. I have to say like another book I read a while back, Physics For Dummies, both books aren’t typical Dummies in being like anyone can read them, which seems a shame to me. Maybe an idea would be if Mark the author wrote a basic book explaining what you need to understand to grasp this book, that might be an idea. Maybe a Basic Signals and Systems For Dummies.

Particle Physics

The book I read to research this post was Particle Physics A Very Short Introduction by Frank Close which is a very good book which I bought from kindle. This book is part of a series of approximately 300 which get an expert in a field to write roughly 150 pages as an introduction to their subject. They are generally fairly although this book is quite complex in places. It is interesting though especially the stuff on colliders like the one at CERN in Geneva which is 27 km long and underground and uses powerful to bend atoms which are sent around a kind of circular tunnel and made collide with each other. They do this kind of thing to find what comprises an atom, make anti matter and also make plasma. Plasma is a state of matter in much the same way as a liquid or gas except it is super heated by something like a star and contains free flowing electrons. If nucleus of an atom was magnified to the extent it was visible to the human eye, the atom would be 10,000 km across. Most of an atom is comprised of nothingness. This is good because a nucleus is extremely dense for its size. There is also a kind of straight tunnel underground at Stanford University in California that is 7 km long where atoms are fired down and smashed together at high velocity. In the case of most atoms, the nucleus is relatively stable and these tend to have a fairly small nucleus with an equal amount of positive and negative charges. Where we get large nucleus’s with different amounts of positive and negative charges, the element decays and gradually turns into something else which is a radio active substance. Not all elements occur in abundance in the Earth’s crust, astatine for example has a total amount of less than 1 ounce and generally has to be manufactured in a laboratory. Atoms are also in a constant flux of being recycled and the atoms you are made from have only been in that form for a relatively short period but are as old as the planet and are 1/3 as old as the universe. I did find this book very interesting and enjoyed reading it.

 

Magnetism

The book I read to research this post was Magnetism A Very Short Introduction by Stephen J Blundell which is an excellent book which I bought from kindle. I think is intended as an introduction to magnetism but does go in a lot of detail and I enjoyed reading it. Magnetism was discovered a thousand years ago in China when it was discovered that a rock called magnetite was naturally magnetic and it was used in compasses. At first it was thought it pointed to celestial north but later it was discovered it points to a magnetic north pole north of Canada. The Earth is like a huge but weak magnet complete with its own electric field. An experiment many school children do in school is sprinkle iron fillings around a magnet and it shows the magnetic field of the magnet. Magnet is connected to electricity for example if you wrap wire around the right kind of metal you can turn it into an electro magnet which only works when electricity is passed through it. All magnets have a north and south pole but it is thought that with the research at the Hadron Collider that single pole magnets are expected to be found. This is a kind of huge underground cylindrical tunnel where charged particles are sent around at high speed and experiments on the basic composition of matter are done.

Superconductivity

The book I read to research this post was Superconductivity A Very Short Introduction by Stephen J Blundell which is an excellent book which I bought from kindle. This book is a good introduction to this subject and covers it in a lot of detail although some of it was a little difficult to understand. Superconductivity was discovered in Germany in 1911 and originally was called supraconductivity and the name was later changed. It was first discovered in mercury at extremely low temperatures. It is often found in substances that don’t normally conduct electricity and is when a current can be passed into a substance and because no heat or friction is generated it will continue to go round a circuit indefinitely. Sometimes pressure has to be added to a substance in addition to an extremely low temperature for it to work but quite a lot of substances particularly the transition metals have this ability. Some applications for this technology are Maglev Trains & MRI Scanners. When first discovered scientists were at a loss in understanding it and working out what it could be applied to. Eventually they hope that substances can be developed that can do this at room temperature & scientists have developed substances that will do it at 138 K which is on the Kelvin scale where 273 K is the freezing point of water. The Kelvin scale is the same as the Centigrade scale but starts at absolute zero which is the coldest possible temperature. I certainly enjoyed reading this book and it is an interesting subject.

Stars

The book I read to research this post was Stars A Very Short Introduction by Andrew King which is a very good book which I bought from kindle. I think you need a good knowledge of maths to understand this book & quite a lot of this book tells you how they calculate things like a stars mass. It’s an interesting addition to this series although I preferred Galaxies & Planets in this series. The universe is twice as old as our sun and so isn’t really as old as you might expect. The biggest stars are about 100 times as massive as the sun and the smallest are about 1/10th. Neutron stars are only about 10 kilometres in radius but have about the same mass as the sun and one cupful of matter from one of these would weigh tons. If a star has more than an initial mass of 7 times the mass of the sun it won’t end its days as a white dwarf and will end as either a nova or supernova. That’s when a star gets very hot and sheds much of its mass making it more bright. The reaction going on in a star is the conversion of hydrogen into helium by fusion or nuclear reaction. This is a chain reaction and some of the helium changes back into hydrogen due to being unstable at these high temperatures. Other elements are made in this reaction but only relatively small amounts. The core of a star tends to be mostly helium. In a red giant the core is compressed until it spills out in a huge reaction making the star much bigger. These stars have a lower surface temperature than the sun hence they glow red.