Week -2

Door-bell:

1. The door bell system as in the model is operated by a controlled switch which is switched on & off every 2 sec.

In order to control the switch we give a input triggering signal using a pulse signal,which is set to a frequency of 0.25,as it has

a period of 4seconds with 50% duty cycle.Based on the time period,frequency,phase delay & pulse width of the pulse waveform

the output waveform characteristics will be decided.

2. When the switch is closed for 2sec the solenoid coil inside the bell is excited by the current this in turn produces a magnetic field which attracts the mechanical plunger to hit the the metal bell.

3. The Velocity & Displacement of the the plunger is sensed by the ideal translational motion sensor to which the solenoid- plunger system is connected at the input.The output is connected to the scope.

4. Ideal output of the system in study should have square wave at its output but its not the same due to damping & friction parameters of the springs in the solenoid.

5. the R & C ports of motion sensor is correctly mapped with R & C ports of the solenoid plunger system.C port is also connected to the translational reference point.

Similarly for electrical circuit there is a Electrical ground.

6. Solver configuration block is attached with the electrical system.This will serve as a common reference point for solving the different equations in the background while running the model.

7. The velocity & displacement ports of the Motion sensor is connected to the scope to view output.

Temperature controlled fan:

1. a repeating sequence stair signal is given as input to physical signal port S of the controlled temperature source.

2. at 25 degree celcius or 298K the value of current output from current sensor(I) is taken previously by connecting a display block & it was calculated as 0.2196

3. This value of 0.2196 is set as a threshold value to the switch selector that selects from the 2 states connected to it.If a value greater or equal to 0.2196 is detected it will allow first input at its output else it will allow the second input.

4. The output of switch selector is then given as input to a switch to switch it on/off based on the threshold value 0.2196 previously taken.

5. This logic will help to switch on the electric circuit whenever there is temperature rise beyond 25 degree celcius & swich it off otherwise.