Random Photographs 003 by Subhankar [Opening a phone and taking external power supply to know how every small component works]

  Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

   

 

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Random Photographs 002 by Subhankar [Opening a phone and taking external power supply to know how every small component works]

  Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

 

 

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Random Photographs by Subhankar [Opening a phone and taking external power supply to know how every small component works]

 Photo by : Subhankar Karmakar

Theme : Technology - Opening a phone and taking external power supply to know how every small component works

                                       

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Compact Disks

In 1982 the fruits of a partnership between Sony and Philips were released to the music-loving public the compact disk or CD was unveiled as the first consumer digital audio format.

These 12 centimeter discs could store up to 74 minutes of perfect quality digital audio and as was famously demonstrated many times over, which're immune from liquid damage could withstand significant scratching and could be played without wearing them down for a theoretically infinite number of times.

                                                      

That's because unlike all previous sound, That's where the sound is encoded as an analog impression of the sound wave on plastic discs or Magnetic Tape the sound on a CD is encoded as a series of samples which function as a set of instructions on how to recreate the sound.

The compact disc was a big freaking deal in many ways. It represented a giant leap inconvenience for the consumer quality of the recorded sound and in raw data storage capacity that last bit wouldn't be too relevant to the Computing industry for some time, but it's solved the Central problem of digital sound needing  time for absurdly massive amount of raw Data,

                                                                                                                before we get too far into the specifics of the compact disc. It's time to dig a little deeper into how digital sound actually works for call . That an analog to digital converter is taken instantaneous samples of the analog signal at a specific sampling frequency. Then a digital to analog converter can recreate the original analog signal with only those samples. Well, a lot of people thought that this can't possibly work.

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From copper to PCB [Last Part] – Photos I have used and Free softwares you can try !

I have used photos from my mobile and some old junk hard disk controller PCBs and other junk PCBs, anyways I have designed one but have not got it manufactured, and for softwares I have used KiCAD – it is free software and you can get it and run it easily and also I have used images from Altium designer software( it is not free ) & Autodesk EAGLE. There is this prominent software which is completely online and is linked with an assembler called the EasyEDA and you can try it too ! Also for KiCAD example and many demo files we have many repositories on internet from OSH-park and other open source hardware companies which give out free complex PCB design files.

In future posts I will try to make a comparison between this PCB manufacturing and IC fabrication !

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From copper to PCB [Part 7] – Placing an order for fabrication of PCB

             

Now that we have designed our PCB we just now have to get the design files exported and get a almost standard output file that a manufacturer will understand and will translate them into good looking PCB. So well there are export options in design softwares which can export the PCB design file in a format called GERBER format and NCDRILL files which then can be submitted online and an order can be placed at PCB manufacturing web sites.

                                  

Now during placing orders also we have a lot of options to choose and one of them is solder mask colour and silk screen colour, now what these two are they are just as we see them, the solder mask colour is the colour of the PCB that is we see green coloured PCB, blue coloured PCB and the markings on them or writings on them are mostly done using white and they are called silk screen colour, the most prominent and most widely seen PCB are green coloured PCB with white text written on them and manufacturing them also cost less.

Later after the PCB gets manufactured and you get in your home then the placing of components will come and the use of solder mask will be prominent as it helps you exposing the contact pads and helps you solder properly without sorting the existing copper contacts and tracks.

The silk screen tells us where to place the components.

Also there is auto assembly offered by many PCB manufacturers and we can pay them so that they buy our components and assemble them using pick and place machines, more about them later !

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The difference and an end to digital sound introduction. Next posts on sampling theorem.

Here's a very crude analogy to explain the difference between analog and digital sound, a vinyl records walls generate an analog signal by moving the stylus left and right as well as up and down its diagonally moved for stereo, but just imagine for a moment that it's just left and right a record directly. That's the analog signal via the motion of the stylus.

But a digital Sound Source is instead sort of like a virtual stylist riding in a virtual Groove. The sound samples are snapshots in time of where the stylist was a DAC will then create an analog signal by running a virtual stylist through this virtual Groove and placing it at exactly the correct location and thus generating the appropriate voltage level as defined by the samples by using a giant list of numbers to recreate sound instead of the Local properties of a plastic disc the sound can be reproduced flawlessly and accurately with no Reliance on the record players cartridge properties. The Integrity of its stylus. It's motor the quality of the vinyl Etc.

The biggest Boon of digital sound was that it eliminated all of the little nuances that might change how a recording sounds digital sound is in a sense absolute but getting digital sound into the hands of the average consumer took a long. It's the amount of raw data generated by sound recording was immense for the standards of the time although 650 megabytes. The data equivalent of the first compact discs is a paltry sum of data in the 21st century.

                                          

It was unimaginably huge in the early 1970s when the first commercial digital sound recording took place for context the Commodore 64released the same year as the compact disc has 64 kilobytes of RAM and that was considered huge for the time a compact disc held Roughly 10,000 times as much data 64 kilobytes of cd-quality audio lasts this long that's not super helpful.

We will continue to look at the methods that were used to store data from digital recordings and we'll discuss the rise of the compact disc as a robust consumer friendly format for digital sound reproduction and distribution.

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From copper to PCB [Part 6] – Design Rules

Now as we have said about routing tracks, we have to understand that this track placing or  routes and via have rules that is the manufacture can only make them physically in a certain way we cannot draw and demand something which is lets say very small and very close placing of copper tracks or components as you have to understand there are physical machines, etching solutions, copper depositors which will work at some point of time on your designed PCB and they have some very real physical and practical limitations which are inevitable.

So, we cannot place copper tracks too close, we cannot place components too close, we cannot make via too close or close to a drill point. We cannot drill too close and so on. Also due to this there are auto routers which help in taking this DRC in account and the software or the algorithm or the computer as we see can just place or draw the tracks all by itself and there is just no need to worry about breaking rules and creating huge trouble.

So in this way our PCB design gets completed. I know this is not a very detailed explanation but it is something or the series is something that can at least give you a rough idea about what is happening.

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From copper to PCB [Part 5] – getting more Physical

So for now we have only discussed about how the two layers are, but depending on the use case, there can be more than two layers and in that case the manufacturers have more copper sand witches sand witched and through our given GERBER information, what diagrams are to drawn on sides are conveyed and all are drawn independently and then sand witched.

Now I have said there are files which convey information, so I have a point to add that these all assembly are done in parts and only the diagram part and drill parts are done with the help of drill machines and photo developers and oxidation and copper deposits etc.

Now as we sort of now know how the PCB is manufactured lets start where we left off, that is after logical diagram and attaching footprints.

So, after all those we just have to draw circuits and those are just how copper tracks will go where the components will be placed, where the power lines will be where the ground planes will be and so on. Also first we just have to place components in place as we want and they are connected with the help of raster nets which are derived from the logical diagram actually, and these raster nets are then to be made copper tracks that is how physically copper will run from one component to another and how the ground planes would be. These running of copper tracks is called routing and has some specific rules.

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From copper to PCB [Part 4] - Intro to Physical View

So, after we have done logical schematic diagram with footprints attached we can now just start drawing on the PCB using our softwares Physical layout editor or a board designer, here what we draw initially is on the top surface of the PCB.

                          

Ok so as I have said surface and we are into physical view now so lets describe how physically the PCB is prepared in the real world in fabrication centre. So, in fabrication centre they start with something called a copper sandwich, which is copper layers on either side with a dielectric material between them, the dielectric material is what the whole PCB gets support on and the top and bottom sides are copper so all the electrical diagrams and contacts and contact pads and via are done on them using first marking with help of UV and then etching.

                                        

                                              

                               

So, first the raw material as described is taken and then the diagrams from the customer are taken and transferred on the copper layers as per given formats. Now for this transfer there is no specific PCB design file, but as we might have heard of we have something called as GERBER files which are files which are generated from the PCB design software and have all the information about how the board drawings would be and how the silkscreen that is all the writings and diagrams would be and how the copper pads will be exposed after the solder mask and a NCDRILL file which tells where the mechanical boundaries are and how the holes are to be drilled.

                                

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