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Silicon - "It's All Sand!"

Before you begin reading..

This is not about-

• People trying out stuff they made in their basements.
• People fighting over patents.
• Inventions of gadgets like the Toshiba Satellite Pro S300.
• Time, Dates and Weather Reports of days in electronics history.

This is about-

• Inventions that changed the electronics industry forever.
• Inventions that form the very basics of modern electronics.
• Inventions that every electronics engineer should know.

J.J. Thomson

1897

Electronics is the ability to control electron flow. It is nothing without the electron. The discovery of the electron marks the birth of electronics itself. If we waive off the Greeks, the Latin & the German, then its safe to say that the electron was discovered by J.J. Thomson when he was playing around in the interiors of the atom. He first discovered the cathode rays. He conceptualized them to be made up of particles smaller than the atom-which were then called the electrons.

1904

The First Thermionic Valve was invented in 1904 by John Fleming. The thermionic diode is slightly different from the semiconductor diode. Though both perform the same function-allowing current to pass through in one direction-The thermionic diode has a cathode and an anode just like the semiconductor diodes have the p and the n junctions. Even before the invention(since 1874), certain crystals were known to have rectifying abilities. Diodes were initially just referred to as rectifiers.

Rectifier Valves

Lee De Forest

1906

The diode valve and the triode valve are both thermionic valves-the diode valve has two electrodes and the triode vale has three. The first triode valve was invented by Lee De Forest in 1906. These valves were the major components of radios for many years(were later replaced by transistors). For this reason, the guy is called ‘The Father Of Radio’. As a matter of fact, he gave himself the title but was never really recognized by the people as ‘The Father Of Radio’. This was largely due to the controversies surround him.

The 3 element vacuum tube was made by adding a control grid to Fleming’s valve. The device was called ‘The Audion’ with which we could control the electron flow. The Audion however, could not provide electronic amplification. However, it formed the basis of the electronic amplifying triode.

The Electrical Experimenter, August 1916. Volume 4.

1947

In 1947, the first transistor was made. It was a  point contact transistor which could amplify electric signals. It was invented at Bell Labs by William Shockley(”the father of the transistor”) along with John Bardeen and Walter Brattain. The term transistor was coined by John R. Pierce.

The way I provided the name, was to think of what the device did. And at that time, it was supposed to be the dual of the vacuum tube. The vacuum tube had transconductance, so the transistor would have ‘transresistance.’ And the name should fit in with the names of other devices, such as varistor and thermistor. And. . . I suggested the name ‘transistor.’

-John R. Pierce, interviewed for PBS show “Transistorized!”

1954

It was in 1954 when Gordon Teal at Texas Instruments created the first Commercial Silicon Transistor. He announced the production of the first Silicon Transistors at a presentation. He started the presentation like usual technical paper presentations without disclosing the achievement. He then amazed the crowd by playing Artie Shaw’s “Summit Ridge Drive.” on a Silicon Transistor. He first played the same music on a Germanium Transistor to bring out the difference. Gordon Teal began his research at Texas Instruments after leaving Bell Labs. Previous studies and inventions were already booming at Bell labs. But perhaps, Bell Labs did not consider it a device too fancy for commercial production.

1958

Jack Kibly was da man of 58′. He invented the first Integrated Circuit(IC) while working for Texas Instruments. He is also the daddy of the first handheld calculator & the first thermal printer. There were transistors already, and transistors needed connecting wires. To reduce the sizes further, they needed to integrate the transistor, the wires and everything else together. Jack Kibly got the idea to make all the components like the resistor, capacitor and the transistor from a single Silicon crystal. This increased performance and reduced costs. The components were close to each other and hence-required much less power supply & showed high switching speeds.

1971

In 1971, Intel introduces the first CPU on a chip-the first Microprocessor. Named The Intel 4004, it was a 4-bit CPU and was the first commercially available microprocessor. A microprocessor is a single Integrated Circuit that performs all the functions of the CPU. The invention further reduced the chip size leading to better performance and reduced costs. Microprocessors are now  apart of almost every electronic device. From small embedded systems to supercomputers-they are an essential component-the heart of all devices.

(The Intel 4004-Image Credit)

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1) Start with the name. Bluetooth got its name from a Danish king! A king called Harald Blåtand (which is Bluetooth when anglicised-converted to English) who united Denmark and a part of Norway into a single kingdom. Bluetooth technology can now be thought as to unite two electronic devices.

Some really cool myths-

• The king wore a blue crown.
• The founders wrote notes with blue ink.
• It sends out waves of “blue” frequency.

2) Bluetooth uses the ISM(industrial, scientific and medical) band which are reserved for scientific and medical purposes-and are not supposed to be used for communication. In this band, it occupies the frequency range 2402-2480 MHz. Wi-Fi also uses the ISM band.

3) Bluetooth can connect up to 8 devices at a time without any interference. This is possible because Bluetooth makes use of FHSS-which stands for Frequency Hopping Spread Spectrum.

In this method of transmitting radio signals, the carrier is switched rapidly amongst multiple frequency channels.

So there’s hardly a chance that two devices will be transmitting signals at the same frequency. Even if they do-they do it only for a very short instant as the frequency is continuously hopping/changing values. Also, The device sending the information(master) switches between the receivers(slave devices) using a kind of Round Robin scheme.

4) Now comes the reason for Bluetooth’s short range. The usual Bluetooth devices work in about 10 m or 32 feet. It’s short range comes from the fact that it sends out signals of low Power(about 1 mW-goes to a limit of 3 mW). And the reason for using low power signals is to avoid interference with other signals using the ISM band.

5) Bluetooth uses a combination of modulation processes. By far, the most favorable modulation for Bluetooth transmission is Frequency Shift Keying(FSK). FSK identifies a positive deviation from the center frequency representing a binary one and a negative deviation from the center frequency representing a zero. The image below illustrates the method.

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(Image Credit)

For a basic idea on whats inside the iPod, how it works and how it is build, let’s try to design our own iPod. Think of the iPod as a computer that is exclusively used to play music. It can further be equipped to add more features like video playback and games.

A Summary

Hardware Needed

• Microprocessor
• Hard Drive/Flash Memory
• Audio Chip
• Added features like Video Chip(if needed)
• LCD Display device
• Rechargeable Li Battery

Software Needed

• Pixo OS 2.1
• iTunes
• iOS(for iPod Touch)

Interface

• LCD/Touch Screen
• Click Wheel

A computer works when its got two things-Hardware & Software. The hardware is the CPU-which we would refer to as a microprocessor. A microprocessor performs all the functions of the CPU on a single IC unit. It has a memory-We need RAM to run the various processes and we also need memory to store the data(music files and stuff).

Consider the RAM already chipped on to the microprocessor as microprocessor memory. We got the microprocessor, now we need memory for data storage. (Note-we can also have RAM and flash memory on our microprocessor) We now got two options for memory-

• A Hard Drive(a highly sensitive one with lots of space)
• Flash Memory(EEPROM using NAND sequential logic)

We can use flash memory if we need about 1-8 GB memory and for all other purposes, we would go for a hard drive. The iPod Classic & Mini use drives while Nano, Shuffle & Touch use Flash Memory.

So, we now got the microprocessor & memory for data storage. We now need an audio chip that can perform the decoding and encoding of the digital stream of data(we are dealing with digital audio here.) This could also be chipped on to the microprocessor like in iPod Shuffle which uses a SigmaTel chip. So, we now have the following-

• A Microprocessor-the heart of the iPod
• An Audio Chip that encodes/decodes audio.
• Either a hard drive or flash memory for data storage

The other hardware we would require is a display device and a controlling device. For display, we use LCD(Liquid Crystal Display) for most of our purposes except when we need a touch screen. For the controls, we use the Click Wheel.

The click wheel is an interesting part of the iPod. It’s plastic when we look at it. But inside it is a metal channel in the form of a grid. The grid hold charge and acts as a capacitance equivalent. Our fingers act as conductors that vary this capacitance. These capacitance variations are interpreted by a control chip that translates the variations into instructions for the microprocessor.

(Image Credit)

We now add a rechargeable lithium ion battery to supply power to our iPod. Well, we are done with the iPod hardware but to make sense of the hardware, we need a platform or software or host-the Operating System is the host-a bridge between the user and the hardware.

The iPod uses the Pixo OS 2.1(found by Paul Mercer after he left Apple to create his own company-Pixo!). The Pixo OS framework uses C++(if you care).  And as everyone would agree,  iTunes would be our desired jukebox/media player software. Now, we all know about iTunes, don’t we?

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All of us use the Pen Drive to store data everyday. We use it like an external storage device, much like an external hard drive. A Pen drive or Flash drive or USB drive has two basic elements-

• Flash Memory (NAND Flash with a crystal oscillator)
• USB (USB Male & a Microcontroller)

The USB(or Universal Serial Bus) just allows the pen drive to communicate with the computer or any other device. Based on their construction, the USB has various versions. The ones which are at work in pen drives are USB 1.1 & 2.

The heart of the “flash” drive is the Flash Memory. This is where digital electronics comes in. There are three kinds of storage media.

• Volatile(info stored does not survive system crashes)
• Non-Volatile(info usually survives crashes)
• Stable(info is never lost-not practically possible-but can be approximated by RAID, etc)

NAND Gate

Our flash memory falls into the category of non-volatile devices. It can be implemented by using both NOR & NAND logic circuits. In flash drives, NAND gates are used.

Digital circuits can be classified into Combinational & Sequential Circuits. A combinational circuit is a combination of a number of logic gates. A sequential circuit is a combination of gates which has a state or memory associated to it. So, a sequential circuit is a combinational circuit with memory.

NAND SR Flip-Flop

Latches and flip-flops are sequential circuits which can store 1-bit of information(either 0 or 1). Further, n flip-flops could store n bits of information.

We could further use an assembly of flip-flops to store data. Such an assembly of NAND flip-flops is used as flash memory.

The crystal oscillator acts as a clock to trigger the sequential circuit. Sequential circuits that use a clock/trigger are called Synchronous Sequential Circuits.

Floating Gate Transistor(FGMOS)

The sequential logic used in the flash memory are realized using floating gate transistors. These are transistors(MOSFET’s) whose gate is electrically isolated-and hence, acts as a floating node.

We have a floating gate(represented by the bold line) and three inputs for the transistor shown.

The use of floating gate transistors makes the flash memory electrically erasable & programmable. It is hence a type of EEPROM. It is a read-only memory that can be erased and rewritten(reprogrammed) electrically-by means of voltage/current.

However, the number of times it can be reprogrammed is limited. We always loose some bit when we format our jump drives.

Put together, our flash memory and the USB configuration forms the USB Flash drive.

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To see an introduction to what namespaces are, go back to tutorial 3. Now, cout is a function in the namespace “std”. Now, there’s another way of using cout without specifying the namespace before hand.

#include<iostream>
int main(
{

a
std::cout<<"Hello Jolly!";
system("pause");
return 0;
}

Here, std::cout means the cout that comes from the std namespace. However, since we would eventually use a large number of output and input statements(ie cout’s and cin’s), we would usually declare the namespace beforehand.

Creating our own namespaces

We can also create our own namespaces. These may contain a number of variables and functions to be used for the particular namespace. We here create a namespace called “my” with a variable of integer type called x.

We will be going into variables and data types in a few tutorials, but here’s ow you create an integer variable called x-

int x;   //creates a variable called x
           //which takes integral values

So, here’s our own namespace-

namespace my{   //creating a namespace
int x;
}
int main()
{
my::x;         //using the namespace variable
}

If we intend to use our variable x a number of times, we could specify our namespace in the program.

using namespace my;  //declare namespace beforehand

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