Aim :
1.Make a Simulink model of Doorbell using solenoid block with the following details:
In the above arrangement, when the switch is closed is 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 second and then
released. Observe the physical movement off the plunnger.
2.Use a thermistor to sense the temperature of a heater & turn on
or turn off the fan as per below condition:
Temperature source; 20 ‘c from 0 to 10 second, 27 ‘c from 10 to 30
Seconds, 23 ‘c from 30 to 50 seconds
Fan condition: ON if the temperature above 25 ‘c, OFF otherwise
1)Doorbell
Theory:
When the doorbell button is pressed, an electric circuit is closed,
which leads to the flowing of electric current through the
electromagnet. The current then passes through the electromagnetic
wire winding. A magnetic field is generated as a result, which is used to drive a sound making mechanism.
Different types off sound making mechanisms are used to generate different sorts of noise.
Procedure:
•First the input is given with the help of pulse generator and its
Connected to electrical switch with the help of a Simulink-ps
Converter and the input is observed by connected scope.
•Then the solver configuration block is connected to the switch.
•Battery block is defined for voltage source.
•The battery is connected to an electrical switch and the switch is
Connected to the solenoid to complete the circuit.
•Then we give the block for solenoid and connect it to an ideal
Translational motion senser to measure the translation motion of
The solenoid, the translation motion of the bell is observed by
Connecting it to a scope with the help for ps-simulink converter.
•Electrical reference and mechanical translation reference
Connected ass earthing.
•Stop time is given as 20 sec
•Initial position of the ideal translation motion sensor is given as 5.
2)Thermistor:
Theory:
A thermistor is a resistance thermometer, or a resister whose
Resistance is dependent on temperature. The term is a combination of
“thermal” and “resistor”. It is made of metallic oxides, pressed into a
Bead, disk, or cylindrical shape and then encapsulated with an
Impermeable material such as epoxy or glass.
There are two types of thermistor: Negative Temperature Coefficient
(NTC) and positive temperature coefficient (PTC). With an NTC
Thermistor, when the temperature increases, resistance decreases.
Conversely, when temperature decreases, resistance increases.
This type of thermistor is used the most.
A PTC thermistor works a little differently. When temperature imcreases,
The resistance increases, and when temperature decreases, resistance
Decreases. This type of thermistor is generally used as a fuse.
Typically, a thermistor achieves high precision within limited
Temperature range of about 50 ‘c around the target temperature. This
Range is dependent on the base resistance.
Procedure:
•First we give input signal with the help of repeating sequence
Stair block.
•The input signal block is connected to ‘s’ port of the controlled
temperature source block with the help of a Simulink -ps convertor.
The. ‘B’ port of the controlled temperature source is
connected to the ‘A’ port(net heat flows through port A) of
thermistor.
•A scope is connected to the input signal of observe the input.
•Then we make a thermistor block and connect a battery to it as a
Voltage source.
•Then we connect resistor block and connect to a voltage
Block in series to measure the voltage flowing through the resistor.
•Display block connected to “V”(v is the physical port that output the
The voltage value) of the voltage sensor with the help of a ps-simulink
Convertor to display the output.
•A conditional switch block with 2 constant blocks of value ‘0’ and
‘I’ is connected of the ”V” port of the voltage sensor
•The threshold of the switch is calculated with the help of
Thermistor equation B(T1/T2) =( T2 * T1 )/( T2 – T1)* In (R1/R2)
•8.29 ohms is calculated ass threshold at 25 degree celsius
And it given as threshold for switch.
•T1 is the first temperature point inn kelvin
•T2 is the second temperature point in kelvin
•R1 is the thermistor resistance at temperature T1 in ohms
•R2 is the thermistor resistance at temperature T2 in ohms
•The conditional switch block is connect to a scope to display the graph
And the output of switch is connected to a lamp. The lamp
Glows red if the resistance across is less than the switch
Threshold meaning the fan if off, if the resistance across is higher
Than the switch threshold the lamp glows green meaning the fan is on.
•Thermal reference and electrical reference is connected to provide earthing.
•The I tial stop time given as
Sec.