Week -2

1. Answer to Doorbell using solenoid block.

Solenoid block represents electromagnetic device who converts electrical energy to mechanical energy. Here we use solenoid block for making doorbell. Normally in electrical doorbell when we apply ac source by closing the switch, current flow through the conductor and coil inside the doorbell. The electromagnetic effect attarct the metal rod and bell sound.

In this simulink model we use battery for voltage source. As we know battery is a DC source and the signal is constant. For pulsating input we use pulse generator. When we apply voltage by battery pulse generator receives constant voltage and produce pulsating DC signal. Here we set the Time period for 2 Sec., pulse width (20% of period), pulse delay is 2 sec. with amplitude of 1.

By above mentioned arrangement the solenoid block receives the electrical energy after close the switch. Solenoid block connected to Ideal Translational Motion Sensor. Ideal Translational Motion Sensor is a sensing device who sense the translational mechanical energy.

Ideal translational sensor has 4 ports. R, C, V & P . where R & C are input ports and V & P are output ports. R & C are Mechnical trnslational conserving ports and V & P are physical signal output ports.

R- Rod (Positive porbe)

C- Case (Refference probe)

V- velocity, m/s

P- position, m

when we apply electrical energy to solenoid that provide mechanical response to Ideal Translational Motion Sensor. By obeserving the movement of two physical signal (velocity & position or plunger movement) we analyse the doorbell function. To view the graph and value of output result we use scope & display.

when pulse start from 0 to 2 sec. we see the velocity movement and plunger movement in graph. As we set it for 2 sec. delay, after 2 sec. means at 4 sec. again we see the velocity movement and plunger movement till 10 sec. . Here the run time we set is 10 sec.

2. Answer to Thermistor to sense the temperature.

For this simulink model we use Repeating sequence stair for generating the temperature source as per the given condition ;

For 0 to 10 sec.- 20 degree C or 293.15 K, 10 to 30 sec.- 27 degree C or 300.15 K , 30 to 50 sec.- 23 degree C or 296 K .

Here we use Conrtolled Temperature source which provides the controlled tempreture to thermistor.

Thermistor is a semiconductor device that has resistance capacity more than a conducting material and less than insulating material. It's resistance varies with the change in temperature or thermal sensitivity.

Thermistor is two types a). Positive Temperature Coefficient (PTC)Type and b). Negative Temperature Coefficient (NTC) Type.

In NTC resistance increases when temperature decreases and resistance decreases when the temperature increases.

In PTC resistance increases when temperature increases and resistance decreases when the temperature decreases.

Here in this simulink model we use NTC as per the requirement.

Fan condition: On when Temp. is 25 degree C or 298.15

In this model two signal to thermistor 1. Battery ( input voltage source) 2. Controlled Temperature Source . The Controlled Temperature source receive signal from Repeating Sequence stair. A registor is connected with thermistor. For sensing the voltage we use Voltage sensor at Thermistor and Resistor.

After that voltage connected to switch. As per the condiotion switch will ON when current flow which again possible if the signal is 1. If less than 0 signal get then switch will in OFF condition.

This switch is now connedted with Controlled Voltage source . This Controlled Voltage source again connected with Translational Electromechanical Converter which is nothing but motor. The Translational Electromechanical Converter receive the electrical energy and converet it to mechanical translational energy. we use this to reffer the fan function. Inside the fan a DC motor is present. In DC Motor when voltage source apply current flow through the conductor which induce magnatic field . The Rotor part of the motor rotates by the force of this magnetic field. This Rotor rotates the blade of Fan and the Fan Run.

Here we use Ideal Translational Motion sensor to sense the mechanical activity of Translational Electromechanical Converter.

To see the result we use Scope here.