Week -2

Theory of Dorrbell:

1.The doorbell is a devicehaving mechanical and electrical component produce sound on presing the button.

2.when swith is pressed the circuit loop is completewhich causes the current to flow through the circuit while passing solenoid it generates the electro magnet 

Principle Behind Doorbell:

solenoid:

 A solenoid is a device comparised of a coil of wire housing, when electrical current is introduced a magnetic field ormsaround the coil it converts electrical energy into mechanical work

pulse generator:

The pulse generator block generates square wave pulses at regular intervals.amplitude,pulsewidth,phase delay,determine  the shape of the output waveform

simulink-ps converter:it converts the simulink input signal to into a physical signal.

switch:switch controlled by an external physical signal.

Battery:it gives the power to the close loop.

Electrical reference:shows connection to electrical ground.

solenoid:electrical characterstics and generated of solenoid.

Ideal translational motion sensor:it is a motion sensor in mechanical translated systems.

ps simulink converter:it converts physicall signal into simulink output signal

Mechanical Translation Reference:reference connection for mechanicaltranslation ports.

scope:it displays signals generated during simulation.

THERMISTOR:

A thermister is defined as a type of resistor is  whose electrical resistance varies with changes in temparature.

Although resistance fluctuate slightly with temparature.

The working principle of thermistor is that its resistance is depedenton its temparature.

we can measure the resistance of a thermistor using ohmmeter.

There are two types of thermistors:

1.Negative Temparature Coefficient(NTC):When the temparature increases,resistance decreases.and hence temparature and resistance inversely propotinal to each other

2.Positive temparature thermistor:

it is reverse relation between temparature and resistance.when temparature increase and resistance also increase.

  RESISTOR:

This is the linear resistor described with 

              V=IR

V=voltage

I=current

R=Resistance

VOLTAGE SOURCE:It implements the volatage source with DC/AC & Noise components

VOLTAGE SENSOR:This is device converts the volatage measured between two points of an electrical circuits into physical signals propotional to the voltage.

ELECTRICAL REFERENCE:

Electrical conserving ports of all the blocks thar are directly connected to the ground

Function of block diagram:

Signal builder:A signal according to the required condition is The giventemparature condition was 20c(293k)

from 0 to 10sec,27c (300k) from 10 to 30 s 23c(296k) from 30 to 50 

conclusion:

In this way the first port use solenoid to convert electrical energy into mechanical energy and made simulink model door bell.

In the scond part,we use the tehrmister to sense the temparature,and according to the given condition, we put the threshold value to the switch for tuen on and turn off the fan