Week -2
Answer 1: The model of doorbell is done and the required model diagram and results have been attached below. The explanation is done below as followed:
The pulse generator is used to create square wave pulses at regular intervals. The block waveform parameters amplitude, pulse width, period and phase delay, determine the shape of the output waveform. The switch block used is controlled by wxternal physical signal.If the external signal is greater than the treshold parameter then the switch is closed, otherwise switch is open. The positive terminal of the battery is connected to solenoid and negative terminal to the switch. The solenoid block is connected with switch and battery and we will get a complete electrical circuit.The port c is connected with mechanical reference.
The ideal translational sensor is connected with solenoid block R to observe the movement of the plunger. Scope is connected with the ideal translational sensor to get the output. PS-Simulink converter is used to convert the physical signal to simulink signal. Solver configuration, each physical network represented by a connected simscape blocks requires solver setting information for simulation.
Result image is uploaded and it shows that time period given is 2 seconds to the pulse generator to open and close the switch. When the switch is closed the solenoid blocks receives electrical power from the battery and the plunger move from port r to c to hit the bell and produce sound.
answer 2: thermistor
Given conditions: 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 temperature above 25°C otherwise off.
Simulink Model Explanation:
signal builder is used to input values as given conditions:
from time 0 to 10 seconds temperature 293.15K
from time 10 to 30 seconds temperature 300.15K
from time 30 to 50seconds temperature 296.15K
controlled temperature source represents an ideal source of thermal energy, that can maintain a controlled temperature difference regardless of the heat flow rate. The temperature difference is set by the physical signal port S. A positive temperature difference causes the temperature at port B to be greater than the temperature at port A. Thermistor is a type resistor whose resistance is based upon temperature. A linear resistor is used in order to control the amount of current from the battery. The voltage sensor is used to convert the voltage measured between two points into a physical signal. Voltage source which represents dc or ac and electrical reference block is given. Solver configuration, each physical network represented by a connected simscape blocks requires solver setting information for simulation.
result image is uploaded and it shows that for 0 to 10 sec fan is off condition because temperature is 293K which is below the treshold 298K. After 10s temperature goes to 300K then the switch will be ON condition as the temperature exceeds 298K. After 30s fan will turn OFF as the temperature comes down to 296K which is below the treshold temperature of 298K.