Week -2

Q 1)Make a Simulink model of Doorbell using solenoid block.

In the above arrangement, when the switch is closed the electromagnet receives electrical power from the battery and pulls the metal arm to hit the bell producing sound. 

Create a situation where the switch is closed for 2 seconds and then released. Observe the physical movement of the plunger. 

Ans:-

1)Input is given by the pulse generator with dealy of 2 sec,then this signal is converted with the help of simulink to ps convertor and is given to the switch.(The input signal can be seen in the below chart).

2)The 2 sec dealy is provided to get the desiered sound output .

3)When the switch is closed the circuit of solenoid and battery get completed resulting in electrical power from battery is given to the electromagnet.

4)Electromagnet get energized and plunger moves,then this movement output is given to the ideal transalational motion which gives outputin the form of graph.

 OUTPUT:-

1)The delay is 2 sec so for every 2 sec the plunger shows movement.

2)i]For initial 2 sec plunger is at rest.(switch is open)

  ii]For next 2 sec the plunger hits the bell.(switch is close,The metal aram get attracted and hits the bell,this creates some short time resonance which get damped shortly. )

3)Output of the following can be seen below.

Q2)Use a thermistor to sense the temperature of a heater & turn on or turn off the fan as per 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

BLOCK USED:(Signal builder,ps to simulink,Controlled temperature source,Thermistor,Voltmeter,Resistor,Solver configeration,Switch,display,scope)

Ans:-

1)The input is created with the help of signal Builder,were all temperature and time values are considered.(293 K from 0 to 10 seconds, 300 K from 10 to 30 seconds, 295 K from 30 to 50 seconds).

2)This input is then given to the controlled temp source block(This block represents an ideal energy source in a thermal network that can maintain a controlled temperature difference regardless of the heat flow rate. The temperature difference is set by the physical signal port S. A positive temperature difference causes the temperature at port B to be greater than the temperature at port A.)

3)This siganl then given to the thermistor,from were an relative value from the voltmeter is taken and a thershold value is obtained.

4)Theroshol value is feeded to switch which have a greater than equal to condition.output can be obtained into the scopes.

OUTPUT:

1)From the output we can observe whenever temperature exides greater than 298k the output is obtained,and switch gets closed.

2)If temp is not greater than 298k switch remains in open position.

3)In this way the fan can be operated for ON/OFF condition.