Simulink model of Doorbell using solenoid block.
- Make a Simulink model of Doorbell using solenoid block with the following details:
In this model, I used the following blocks with their functions:
1- Solenoid: Electrical energy into kinetic energy, The Solenoid block represents the electrical characteristics and generated force.
2- Battery: Gives supply for the solenoid.
3- Switch: To complete the connection.
4- Pulse generator: The Pulse Generator block generates square wave pulses at regular intervals pulse generated from PG is converted to Simulink to physical signal and given to switch for perform switch function.
Followings are the values for PG: amplitude:1, pules width:20, perid:10secs, phase delay:2.
5- Ideal translational motion sensor: Physical movement done by the solenoid is sensed by the Ideal translational motion sensor
6- fundamental blocks for output and electrical, mechanical references.
Model process:- when the switch is closed the electromagnet receives electrical power from the battery and pulls the lever, Ideal translational motion sensor sense that movement and gives the output by scope.
output: 
Observations: For 0 to 2-sec output is null and from 2 and 4 it gives oscillation.
Use a thermistor to sense the temperature of a heater & turn on or turn off the fan as per below conditions:
condition:
Temperature source: 20 °C from 0 to 10 seconds, 27 °C from 10 to 30 seconds, 23 °C from 30 to 50 secs
Fan conditions: ON if the temperature above 25 °C, OFF otherwise
model: 
In this model I used following blocks with their function.
1. thermistor: temperature sensing element, Negative temperature coefficient thermistor using B-parameter equate.
2. controlled temperature: This block represents an ideal energy source in a thermal network that can maintain a controlled temperature difference regardless of the heat flow rate.
3. signal builder: function to create and access Signal.
4. DC voltage source: The DC Voltage Source block maintains a time-invariant (constant) voltage across its output terminals, independent of the current through the source.
5. voltage sensor: The block represents an ideal voltage sensor, that is, a device that converts voltage measured between any electrical connections into a physical signal proportional to the voltage.
6. switch: The Switch block passes through the first input or the third input signal based on the value of the second input. The first and third inputs are data input. The second input is a control input. Specify the condition under which the block passes the first input by using the Criteria for passing first input and Threshold parameters.
7. fundamental block for output and electrical and mechanical reference.
output:
Observation: Output shows that switch is ON when the temperature is above 25 which is in an interval of 10 to 30 secs.