Week -2

1.) DOORBELL MODEL :-

Here. Doorbell consists of the main parts which include a solenoid, battery as a source, switch & bell. Here, the important part is the Solenoid on which the working of the plunger i.e movement depends. A solenoid is just an electromagnet where the coiled wire surrounds a metal piston. The piston contains magnetically conductive metal, so it can be moved backward or forward by the electromagnetic field. A magnetic field is produced here with the help of battery source

SIMULINK MODEL :-

WORKING :-

INPUT :-

also stop time used is 10 sec

OUTPUT :-

1.)

here graph is obtained at the default value setting of the solenoid block in the below figure

2.)

here the value of damping is changed which is eliminating the excessive oscillations and vibrations for smooth signal intensity

according to the above example of the output. we can change the various input parameters to get the output with smooth intensity signal. For Ex we can change the spring constant, plunger mass, etc according to the conditions for the desired output.

RESULT :-

Here we run the model for 10 sec as it is a stop time provided here. The graph is obtained for 10 seconds. From the graph, it can be seen that due to the delay of 2 sec at the initial stage, the position of the plunger is at O. But after that, for the next 2 seconds, the solenoid will engage and there will be movement of the plunger. Again for the next 2 sec, the position will come to O and for the next 2 seconds plunger will show displacement. This process continues for a total of 10 seconds according to the stop time provided.

2.) THERMISTOR MODEL :-

A thermistor is a resistance thermometer or a resistor whose resistance is dependent on temperature. The term is a combination of "thermal" and "resistor".

There are two types of thermistors: Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC). With an NTC thermistor, when the temperature increases, resistance decreases. Conversely, when the temperature decreases, resistance increases. This type of thermistor is used the most.

A PTC thermistor works a little differently. When temperature increases, the resistance increases, and when temperature decreases, resistance decreases. This type of thermistor is generally used as a fuse.

SIMULINK MODEL :-

WORKING :-

1) Here NTC thermistor is used as temperature sensors to sense the temperature change of the heater & turn on or turn off the fan

2) To satisfy the given conditions of temperature range here repeating sequence block is used with a sample time of 10 sec giving required temperature values. As this block is a Simulink block, hence Simulink to PS converter block is used to convert and provide the physical signal to a thermistor through a temperature source

3) As the thermistor uses resistance for temperature serising a resistor is connected in series with the thermistor and voltage is measure across the resistor by connecting the voltage sensor parallel with the resistor Also, the battery is connected as an electric source provided with reference

4) First of all, the constant output of the voltage sensor for a temp of 298 K (25 c) is measured which is a threshold value given to the switch as an 'if condition for the fan to turn ON or OFF, Here input temperatures that we have designed will compare their respective values with the standard value for greater than equal to or less than to the value of 298 K and activate the switch accordingly. Here constant threshold value for 298 X is noted as 0.01189 V

So as in actual practice, when the temperature signal provided at the thermistor is greater than 298 Kits resistance decreases, and the voltage will increase than 0.01189V and vise versa.

5) Now switch has 3 inputs. We will provide the above threshold value to the middle port. Two constant blocks with values 1 and 0 are connected to turn a switch ON or OFF respectively. If the switch condition is satisfied then the signal will pass to the DC motor with the switch ON using a constant block with value 1 otherwise switch will remain OFF using a constant block with a value of 0.

6) Now, when the condition of ON will satisfy, the signal will pass through the controlled voltage source to the DC motor and it will turn on which will give angular velocity that can be observed at the end in the graph through the scope.

7) Different 'Reference blocks for a fixed reference point and solver configuration' blocks to solve the simscape model are provided wherever necessary.

INPUTS :-

OUTPUTS :-

RESULTS :-