Week -2

Q 1. Make a Simulink model of Door Bell using solenoid block with the following details.

Condition Given : Create a situation where the switch is closed 2 seconds and then released .

Solution : Blocks used –

• Solenoid Block – used as a bell ringer

• Pulse Generator – To provide input signal as per the given condition (2 sec)

• Ideal Translation Motion Sensor - Used to sense the solenoid motion and send it to scope

• Battery – To provide supply to solenoid coil to create a magnetic field

• Switch – used to ON and OFF the bell input source

• Mechanical Translation Reference And Electrical Reference Blocks for System

• PS-Simulink And Simulink -PS Converter Blocks

• Solver Configuration Block – used to solve internal mathematical equation

Model file is attached below name a Bell_model

Result :-

As above plot shows the result that as per the given condition the switch is closed for 2 seconds and bell is rang off after 2 sec and on again .

Q 2. Use a thermistor to sense the temperature of a heater & turn on and off the fan as per the below condition

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

Solution: Block Used –

• Thermistor Block - Negative Temperature Coefficient (NTC) thermistor used having the specification that when the temperature is increasing the resistance is decreases

• Repeating Signal Stair – with the help of this block we can given specific input values to our model.

• Thermal Reference Block – this block provide required initial condition to connect thermal block

• PS-Simulink block – Which convert physical system signal to Simulink signal

• Controlled Temperature Source(CTS) - Provide thermal output signal

• Switch Block – Which is on and off as per threshold and the applied inputs

• Resistor – Used as a Heating element or heater

• Scope – Which shows output with respect to time

Input temperature conditions are provided by repeating sequence stair block as given below-

20 °C for 0 to 10 seconds = 293 K

27 °C for 10 to 30 seconds = 300 K

23 °C for 30 to 50 seconds = 296 K

As per the given conditions the fan is on only when the temperature is above 25 °C that is 298 K

Thermistor temperature sensing Model simulink file is attached below name as temp_model

Result :

The below plot shows the result , at 0 to 10 sec the fan is OFF from 10 to 30 sec fan is ON so its shows a spike at that time interval when temperature is above 298 K . after that from 30 sec to 50 sec fan is again OFF because the temperature is below 298 K that is 25 °C .