Week -2

Door bell

Objective:

The objective is to make a door bell using solenoid and observe the movement of the plunger.

Working:

At first when the input is given through the pulse generator the switch closes

In this case when the switch is closed for a time of 2 sec the circuit closes and an electromagnet field is created around the solenoid. This pulls the plunger towards the bell.

Here the solenoid is connected to an ideal translational motion sensor. The sensor records the translational movement of the solenoid.

Here the movement of the plunger id dependent on the value of current flows through it.

When the current values are decreased or the switch is turned off the force acting on the plunger decreases gradually and comes to rest as shown in the graph.

Thermistor

Objective:

To build a Simulink model with thermistor which senses the temperature of the room and switch on a fan.

Model:

Thermistor:

The word is a combination of thermal and resistor. Thermistors are widely used as inrush current limiters, temperature sensors, self-resetting overcurrent protectors, and self-regulating heating elements.

It senses the temperature from the source and the resistance value changes. The voltage in the circuit can be controlled by the applied temperature

There is a voltage sensor connected across the resister which senses the voltage from the thermistor.

A Repeating Sequence Stair is given as input to the thermistor through a controlled temperature source.

Sequence Stair block is given below.

That voltage is given as the threshold voltage to the switch. When the voltage value reaches the threshold value the switch closes, on the other hand when the voltage is below the threshold value switch opens.