Week -2

1) Make a Simulink model of Doorbell using solenoid block

Principle of solenoid : The solenoid simply works on the principle of “electromagnetism”. When the current flow through the coil magnetic field is generated in it, if you place a metal core inside the coil the magnetic lines of flux is concentrated on the core which increases the induction of the coil.

Electromagnetism is based on number of turn of coil or the current passing through the coil.

• first we use the step block to ON the switch, so we gievn step time 2 sec. then we use simulink PS Converter to Converts the unitless Simulink input signal to a Physical Signal to switch ON the switch. the output of the Simulink PS converter is given to Single pole single throw (SPST) Switch which is controlled by an external control signal vT. If vT is greater than the threshold, then the switch is closed, otherwise the switch is open.
• when the switch is ON, A positive current from the electrical + to - ports results in a negative force (i.e. pulling force) acting from the mechanical C to R ports.
• then the movement of plunger ( hammer) will hit gong. thats create noise.

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

Temp Condition : 1) 20 degc from 0-10 sec

2) 27degc from 10-30 sec

3) 23 degcfrom 30-50 sec

Fan Condition : ON, i f the temp above 25 C otherwise OFF.

what is mean by thermistor : its a combination of thermal and resistor. Resistance changes with change in temperature.