Week -2

AIM:-

1. To make a simulink model of Doorbell using solenoid block.

2. To use a thermistor to sence temperature of heater & turn the fan on/off as per the conditions.

STUDY:-1

Theory:

The doorbell works on the principle of electromagnetism. It uses a solenoid. When the switch is in close condition, electricity is passed into the solenoid which creates an electromagnetic field. The plunger moves due to this electromagnetic field and hits the bell to produce a sound.

Simulink Model:-

Input parameters:-

Input Signals:-

Model Explanation:-

1. One end of the battery is connected to the switch while the other end is connected to the solenoid.

2. The switch is given an input signal using pulse generator.

3. The other end of the switch is connected to the solenoid. A reference is also provided for the circuit.

4. The plunger part of solenoid is connected to the motion sensor to get the appropriate output of the plunger. A mechanical translational reference is provided for the circuit.

5. A scope is connected to view the output from the motion sensor.

OUTPUT:-

Conclusion:-

The doorbell model was created and executed. We observed that there was a change in position of plunger when electricity was passed into the solenoid.

STUDY:-2

Temperature source:20 c from 0 to 10 sec, 27c from 10 to 30 sec, 23c from 30 to 50 sec. Fan conditions: ON if the temperature above 25c, OFF otherwise.

Thermistor:-A thermistor is a type of resistor which has a propery of increasing its resistance linearly with respect to increasing temperatere.

Simulink Model:-

Model Explanation:-

1. A thermistor is used along with a resistor and a battery to create a circuit.

2. The temperature is connected to an ideal temperature source and a voltage sensor is provided across the resistor to measure the voltage difference.

3. The temperature source is provided with input signals as per the given conditions in question.

4. The output from the voltage sensor is given to the switch.

5. A DC motor is used which has its one end connected to switch output and other end to a rotational motion sensor.

6. The output from motion sensor is connected to scope to get both angular displacement and velocity of the motor.

Conclusions:-

The thermistor model was created and executed. We were able to switch ON the fan at a particular temperature as per given conditions.