The digital electronic system is that process that allows you operate that digital device you have. It can be as simple or as sophisticated as you want to make it seem….mostly sophisticated to many. Either way, there is a digital electronic activity going on oblivious to many.
AIMS
At the end of this discussion you will know
– How switch logic enables binary conversion.
– How the binary number system is applied on to circuits.
– Why multiplexers and other forms of reducing digital bulk are used.
– What Adder are
SWITCH LOGIC AND BINARY CONVERSION
Switch logic is what enables electronics perform the various tasks they do such as typing. A man named Gorge Boole came up with this. In order to understand it, one would have to put into context the simplest thing that comes into play in these devices. That in essence would be a chip that contains silicon which from its semi-conductive nature will allow it switch currents on and off very fast. In this process, there is basically an OR circuit and an AND circuit. (Watson) The OR circuit in digital electronic systems is that circuit which will allow current using two possible routes to pass if either route is completed. In AND circuit, current will only pass if both switches are closed. If one isn’t, then current will not pass. These circuits can be further made complex by using an equivalence circuit which combines and OR circuit and an AND circuit. If currents run in this circuit, it means that the current for either OR circuit and the AND circuit on one side have been completed. The other is the exclusive or XOR circuit which allows current pass if switches are closed on side but both cannot be closed at the same time. The other catchy thing about this is that a choice can be made in which circuit one would prefer current to flow. Naturally, when current flows or does not, it is termed among others but most popularly as ‘true’ or ‘false’ depending on whether current flows or not. If it does it is true represented as ‘1’ or as ‘0’ if it doesn’t. (Watson) This is what is referred to as binary number system. It is therefore a way of representing a how circuits that operate in either of the two states behave.
Ever wondered why earlier computers were so big? Well, it’s all in this chip. This forms the basis of all the operations in the computer if we left out the silicon circuits and the silicon itself. I was not possible then to minimize the size of data space and put them in really tiny chips called microchips. Therefore, they used much larger parts to store and operate data space because there wasn’t any knowledge of minimizing them. The first computer whose name was baby occupied a whole room. Even with its size, it could only store 1024 bits. This and the computers that followed had large chips but modern chips are smaller with more circuits allowing them have more computing power in the simple process that’s on and off.
DIGITAL LOGIC GATES
What makes binary numeration so important to the application of digital electronics is the ease in which bits may be represented in physical terms. Because a binary bit can only have one of two different values, either 0 or 1, any physical medium capable of switching between two saturated states may be used to represent a bit. (Berkeley) Therefore once a device can represent these binary bits and represent them with numbers it can then be conclusively said that a computing device has been made.
Basically, this will make the use of the NOT gate which give an opposite output to it input signal. The others are the OR gate, the AND gate, the XOR gate and the NAND gate.(Berkeley) In this modern times they come in the form of diodes and transistors.
These binary numbers are what are represented as switches with one switch represented as ‘1-0’. It takes a regular set of the same numbers in a distinct pattern to represent many more switches. The binary number can represent anything from number referred to as decimals to characters and alphabets. (Watson) A count of zero to twenty using this system will give the following
DECIMAL BINARY
0 0
1 1
2 10
3 11
4 100
5 101
6 110
7 111
8 1000
9 1001
10 1010
11 1011
12 1100
13 1101
14 1110
15 1111
16 10000
17 10001
18 10010
19 10011
20 10100
You will notice that representing it in binary characters in is significantly longer. Several attempts have been made to make work easier and less tedious. (Berkeley) Some have proven successful while others have not. One such successful story is the hexadecimal system that uses a place-weighted system with a base of sixteen, binary arithmetic, concept of overflows and bit groupings.
In order to create a circuit capable of binary addition you have to use adders. This is a digital circuit that will carry’s out the tasks of adding numbers. Most common adders operate on binary numbers such as the 3-bit adder. They are also widely used in other parts of processors.
http://inst.eecs.berkeley.edu/~ee100/su07/handouts/IntroductionToDigitalSystems.pdf
http://www.watson.ibm.com/leo/introelect/IntroElectro_handout.pdf
