Week -2

1)Make a Simulink model of Doorbell using solenoid block with the following details:

• Solinoid(simulink physical model) used to represent bell movement with electrical supply.
• Ideal translation motion sensor used to sense bell translation motion.
• pulse generator of pulse width 2 second used to keep the switch for for 2 sec.

2) Use a thermistor to sense the temperature of a heater & turn on or turn off the fan:

• controlled temperature source used to provide heat to thermister.
• signal bulder block used to desired conditional input to thermister.
• Voltage & current sensor used to measure resistance across Thermistor.

• R(T) = R0*exp(B*(1/T-1/T0)) these formula used to get the value of resistace at temp=(25+273)K .>R0=resistance at T0=273K=1000ohm.>B=temparature constant>R(298K)=344.1ohm>344.1ohm set as the condition for SWITCH.>As per the challange,thermistor should exihibit positive temp cofficient.>Used thermistor has negative temp cofficient,if we reverse the conditional output of switch     ,which will create output signal as 0 when resistance greater 344.1ohm.>This condition used in a switch to turn on a DC motor .

• output responce is mentioned in the attached output.
• motor on for t=10-50sec. when temperature is greater than 25 deg celcius.
• motor shows inrush current at starting of fan then gradually get stable and zero at t=50 sec.