Week -2

Aim-

To make Simulink model for a doorbell using solenoid block.

As per given conditions switch is closed for 2 seconds & then released.

The pulse generator is used to create square wave pulses at regular intervals.Switch block is controlled by external physical signal & if the external physical signal is greater than the switch is closed or else switch is open.

The signal from the pulse generator was converted using the Simulink PS converter and is given to the input switch. A solenoid introduced and battery is connected to the it. The voltage of the battery connected was made as same as that of the rated voltage of the solenoid. The switch is also connected to the same circuit.

The simulation was run for 30 seconds and result obtained is shown above. It can be observed that at each 2seconds bell was ringing.

Result:

Aim:

To use thermistor to sense temperature of a heater and turn on/off the fan.

Temperature source – 20 from 0 to 10 seconds, 27 from 10 to 30 seconds, 23 from 30 to 50 seconds.

Fan conditions – ON if temperature above 25 degrees , OFF otherwise.

In this model the signal block is used to get temperature signal for the controlled temperature source (heater).The temperature of the heater is supplied to thermistor to sense it. Now in order to run the fan when temperature reaches the value of 298K we have to trigger the circuit with some external supply of battery and as there is no device to calculate the resistance value of thermistor so we have attached another resistor in series across the terminal in series. The voltage sensor is attached across the resistor to calculate the voltage drop into it & this voltage drop value is inputted as threshold value to the switch to start the fan & fan will go on when threshold value is more than 0.21.

Result:

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