Getting Started with Electronics

What is an Embedded System?

The integration of hardware and software to perform specific functions, minimizing the need of human control is an embedded system.

·         Digital watches and cameras.

·         Calculators

·         Timer system in washing machines

·         Temperature monitoring systems

·         Automatic security systems

Embedded hardware, once programmed, is dedicated to perform that task forever.

It is designed to interact with human elements as well as external environment with the help of sensors.
Systems that doesn’t require time deadline to be completed, are called non-real time embedded systems.
Systems which are programmed to perform tasks, being controlled by time deadline are called real time embedded systems.

Components to design embedded systems

Resistors

These are the basic elements which are used to limit voltage or current supply into the appliances.

Colour	value
Black	0
Brown	1
Red	2
Orange	3
Yellow	4
Green	5
Blue	6
Violet	7
Grey	8
White	9

·         First two bands from closer side represent the integer part.

·         The next band provides power raise to 10.

·         Last band shows tolerance having different colour code as-

- 2% for red

- 5% for gold

- 10 % for silver

Capacitors

To remove the traces of noise from our output and to obtain a stabilized supply, capacitors are used.

The two types of capacitors we will be using to design our circuit are-

Ceramic capacitors

·         Parallel plate capacitors with ceramic as dielectric filled in between.

·         Do not have fixed polarity.

      Value written on it gives its capacity, for example if written 104, means 10x10⁴ pF.

      

Electrolytic capacitors

·         Cylindrical capacitors with electrolyte filled in between.

·         They have fixed polarity determined by covering over the capacitors.

·         If not connected in right polarity it may blow off.

Voltage regulator IC 7805

This is a 3 pin IC used to regulate voltage to a fixed value of 5V.

Last two digits on IC number represent the output voltage given by it.

Current up to 0.5A can be obtained from the regulator IC.

Two capacitors of 0.1pF are used at input and output ends to filter noise in respective supply.

npn Transistor BC547

The transistor holds ‘CBE’ i-e collector, base, emitter respectively in same order, when observed from flat face.

Diode 4007

This component converts bilateral current flow into a specific direction.

It can be used to avoid reverse flow of current or to prevent circuit from any blow off.

Silver line represents the negative biased point.

Diode 4148 is a zener diode.

LED

These emit energy in the form of photons due to electronic transitions in visible region of spectrum.

It performs the same what a diode can, beside, it can also be used to show output.

The current through LEDs must be lesser than 20mA, that’s why it is suggested to put 220 ohm resistor in series to it.

The one with shorter leg of LED is negative terminal.

Bread Board

Instead of wasting money on Printed Circuit at the very initial stage, we can test our circuit on bread board. A structure with bread like pores, through which connections are internally made to connect through the complete circuit, is a bread board.