Week -2

task1

create a simulink model of doorbell using solenoid

in this simulink we have used following blocks

pulse generator

battery

solenoid

swich

ideal translation motion sensor

scope

in given problem their is mention od condition the swich is open and close every after 2 sec.

so we have mentioned the the time delay in pulse generator of 2 sec.

the pulse generator is used to create square block as shown below in the fig. the wave is formed in regular intervals.

WHAT IS A SOLENOID?

At the simplest level, a solenoid is a length of wire coiled around a core. The core often has two parts-- a stationary core and a moveable one, which is the armature. The two parts are spring-loaded.

When electrical current goes through the wire, it creates a magnetic field that moves the armature away from the stationary core (or toward it, depending on the solenoid’s use and construction). When the current stops, the spring snaps the armature back into its original position.

This back-and-forth motion makes this type a linear solenoid, although there are also rotary solenoids that are a little more complex.

To function, a solenoid must have three things:

• Coiled wire
• A movable core
• Electricity

Working of solenoid

A solenoid works by producing an electromagnetic field around a movable core, called an armature. When compelled to move by the electromagnetic field, the motion of that armature opens and closes valves or switches and turns electrical energy into mechanical motion and force.

results-

as we have seen the pulse generator producing square wave that means it open and close the electric circuits by this wave formation. as circuit get closed the solenoid procduces electromagnetic signals and plunger movement occures and we hear a ring of bell. the conversion of the physical movement into electric formation is seen in the second scope.

TASK 2

in task 2

Use a thermistor to sense the temperature of a heater & turn on or turn off the fan as per the below conditions:

Temperature source: 20 °C from 0 to 10 seconds, 27 °C from 10 to 30 seconds, 23 °C from 30 to 50 seconds

Fan conditions: ON if the temperature above 25 °C, OFF otherwise.

now here we have used following elements to create the simulink-

signal generator

controlled temprature source

thermistor

voltage sensor

resistor

switch

battery

in this simulink the signal genertor have used the main input source for the circuit. in the signal generator we have created a signal of diffrent temprature as mentioned in conditions in degree kelvine.

we have used simulink to ps convertor for the input of the system.

the input of this is provided to controled temprature source and the output of this is provided to the thermistor.

thermistor is temprature sensing device which convert the the thermal signal into the electrical signals the thermistor is operated by an electric circuit.

the voltage sensor is also used to sence the change in the voltage at perticular temprature.

now in our case the voltage in our system at 25 c is 0.01196. this voltage signal is passed through a switch and if the voltage in switch is pass over the set voltage. the circuit get closed and fan get start, i.e. the temprature in the room pass the 25'c , and if goes below the set voltage the circuit get open and fan stop.

the imange below it the result imange shows the open and close of circuit at diffrent temprature range.