PLUNGER AND THERMISTOR

AIM:

1. To determine the movement of doorbell plunger using simulink.

2. Sense the temperature of a heater by thermistor using simulink.

KEYWORDS: Solenoid, Thermistor, Resistor

SOFTWARE: Matlab, Simulink

OBJECTIVE:

• To determine the movement of doorbell plunger by applying certain condition.
• To sense the temperature of the heater by using thermistor and operate the fan accordingly.

INTRODUCTION:

Study 1:-

In the above figure,it consists of battery, switch, solenoid and plunger. We need to identify the movement of plunger according to the condition given i.e., the switch is closed for 2 seconds and then released. By using simulink the input is given as pulse generator which is connected to switch input. The switch terminals is connected to the DC voltage source and solenoid respectively. A solenoid is a coil of insulated wire wound on a rod-shaped form made of solid iron, solid steel, or powdered iron which produces magnetic field when electric current passed through it. It is a electromechanical device. Devices of this kind can be used as electromagnets, as inductors in electronic circuits etc., The solenoid plunger is connected to the ideal translational motion sensor which senses the motion of plunger. The sensor sends the signal to output block. In brief the model is converting the electrical energy into mechanical energy. I this model solver configuration is used to solve the model wrt the refernce.

Study 2:-

In the above model, it consists of DC voltage source, Thermistor, resistor, voltage sensor, reference, controlled temperature source, temperature sensor, converters, display, scope and signal builder. Signal builder is used as input inorder to achieve the condition (Temperature source: 20 °C from 0 to 10 seconds, 27 °C from 10 to 30 seconds, 23 °C from 30 to 50 seconds. Fan conditions: ON if the temperature above 25 °C, OFF otherwise). Input from signal builder supllies to temperature controlled source which is connected to temperature sensor. The temperature source is connected to the thermistor and temperature sensor. Thermistor is used to sense the change in resistor value which inturn change in temperature. A thermistor is a type of resistor whose resistance is dependent on temperature, more so than in standard resistors. The word is a combination of thermal and resistor. Thermistor and resisitor are connected in series which is connected to DC voltage source as input. To measure the output voltage, voltage sensor is used which controls the fan by sensing thershold value. Initially, for 295 K we need to get the thershold value and keep it as standard and apply to the switch condition which measure the value in every change in temperature.

OUTPUT:

Study 1:-

FIGURE-1

Study 2:-

FIGURE-2

FIGURE-3

CONCLUSION:

1. The movement of doorbell plunger is obatined by graph for repeating condition as shown in figure-1 by changing pulse width and pulse delay. Pulse delay is given as 2 secs and the position as 2mm. The initial position of the plunger is given as 0, run time as 10 secs.

2. The fan is controlled by using thermistor which is shown in figure-2 and the temperature changes aslo obtained in graph by using temperature sensor as shown in figure-3. In figure-2, the switch is OFF for 0-10 secs and ON for 10-30 secs and again OFF for 30-50 secs, because when the tempeature is above 298 K the fan will be ON else OFF.