Friday, April 25, 2014

Activity in Digital Design

1.)

Solve for : IT , I1, I2, I3

2.) RED RED BLUE GOLD

3.)0RANGE RED BROWN SILVER

Thursday, April 24, 2014

LOGIC GATES and COMBINATION

    logic gates
           - is an idealized or physical device implementing a Boolean function; that is, it performs a logical operation on one or more logical inputs, and produces a single logical output. Depending on the context, the term may refer to an ideal logic gate, one that has for instance zero rise time and unlimited fan-out, or it may refer to a non-ideal physical device .
              Logic circuits include such devices as multiplexers, registers, arithmetic logic units (ALUs), and computer memory, all the way up through complete microprocessors, which may contain more than 100 million gates. In practice, the gates are made from field-effect transistors (FETs), particularly MOSFETs (metal–oxide–semiconductor field-effect transistors).

Combination of Basic Logic Gates

The OR, AND and NOT gates are the three basic circuits that make up all digital circuits. We shall discuss a few combinations of theses basic circuits.

(I) NAND Gate: It is combination of AND gate is connected to the input of a NOT gate as shown in Fig. (a). Clearly, the output of a NAND gate is opposite to the AND gate. This is illustrated in the truth table for the NAND gate. Note that truth table for NAND gate is developed by inverting the output of the AND gate.
The Boolean expression for NAND function is

This Boolean expression can be read as Y = not A . B. TO perform the Boolean algebra operation, First the input must be AND and then the inversion is performed. Note that output from NAND gate is always 1 excepted when all of the input are 1.Fig. (b) shows the logic symbol for a NAND gate. The title bubble (small circle) on the right end of the symbol means to invert the AND.


Fig. (a)		Fig. (b)

Inputs		Outputs
A	B	AND(Y')	NAND(Y)
0	0	0	1
0	1	0	1
1	0	0	1
1	1	1	0

Truth Table of NAND

(II) NOR Gate: It is a combination of OR gate and NOT gate. In other words, output of OR gate is connected to the input of a NOT gate as shown in Fig. (c). Note that output of OR gate is inverted to form NOR gate. This is illustrated in the truth table for NOR gate. It is clear that truth table for NOR gate is developed by inverting the outputs of the OR gate.


Fig. (c)		Fig. (d)

Inputs		Outputs
A	B	OR(Y')	NOR(Y)
0	0	0	1
0	1	1	0
1	0	1	0
1	1	1	0

Truth Table of NOR

The Boolean expression for NOR function is:

The Boolean expression can be read as Y = not A or B. To perform the Boolean algebra operation, first the input must be OR and then inversion is performed. Note that output from a NOR gate is high(1) only when all the inputs are low (0). If any of the inputs are high (1) the output is low (0). fig. (d) shows the logic symbol for a NOR gate. The bubble (small circle) at the Y output indicates inversion.

Different Types of Resistors

Resistor

- an electric resistor is a two-terminal passive component specifically used to oppose and limit current. A resistor works on the principle of Ohm’s Law which states that voltage across the terminals of a resistor is directly proportional to the current flowing through it.

Resistor Color Code Information :

Tuesday, April 15, 2014

Ohm's Law
-
Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance,one arrives at the usual mathematical equation that describes this relationship:

$I = \frac{V}{R},$

where

I

is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.
The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. He presented a slightly more complex equation than the one above (see History section below) to explain his experimental results. The above equation is the modern form of Ohm's law.
In physics, the term Ohm's law is also used to refer to various generalizations of the law originally formulated by Ohm. The simplest example of this is:

$\mathbf{J} = \sigma \mathbf{E},$

where J is the current density at a given location in a resistive material, E is the electric field at that location, and σ is a material dependent parameter called the conductivity. This reformulation of Ohm's law is due to Gustav Kirchhoff.

Ohm's Law Formulas

Deriving values horizontally across columns is allowable as per the principles of series and parallel circuits:

Tuesday, January 28, 2014

activity diagram

activity diagram ( 01/28/14)

Monday, January 20, 2014

computer compiler - is a computer program (or set of programs) that transforms source code written in a programming language (the source language) into another computer language (the target language, often having a binary form known as object code). http://en.wikipedia.org/wiki/Compiler

examples of compiler :

Assembler 8051

Assembler x86 with TurboAssembler

MS-Dos Batch language

MS_SQL