FAN CONTROLLED BY USING TEMPERATURE SENSOR

BY B NANDEESH

CONTENTS

Objective of project Introduction Components used Circuit diagram Working Advantages Disadvantages

OBJECTIVE OF PROJECT

Our object of making this project is for reducing the power consumption. And also to assist people who are disabled and are unable to control the speed of fan.

It may also be used for monitoring changes in environment. In near future, it can also be used in different industries and electronic devices.

INTRODUCTION A simple introduction about the temperature controller circuit.

This circuit project is mainly used for indicating temperature , controlling temperature.

The circuit exploits the property of sensor to operate the Fan. A sensor is a type of transducer

In a broader sense, a transducer is sometimes defined as any device that converts energy from one form to another.

The component that made up the temperature sensor is known as thermistor

Thermistor is a kind of temperature dependent resistor and its resistance varies depending on the temperature in its vicinity

There are two types of Thermistors Negative Temperature Coefficient Thermistor (NTC) Positive Temperature Coefficient Thermistor (PTC).

NTC Thermistor decreases its resistance when the temperature increases

PTC Thermistor increases its resistance when the temperature increases.

A small DC fan increases or decreases its speed as per the temperature change. When the temperature decreases below a certain level, Fan automatically turns off.

The main principle of this project to monitoring and to control the temperature.

 

COMPONENTS USED:- Temperature Sensor Resistor Capacitor DC power supply LED Diodes NPN Transistor Motor transformer Electric Fan 12V Vero board propeller

RESISTOR:-

A resistor is a two-terminal electronic component that produces a voltage across its terminals that is proportional to the electric current through it in accordance with Ohm's law: V = IR

The primary characteristics of a resistor are the resistance, the tolerance, maximum working voltage and the power rating. Other characteristics include temperature coefficient, noise, and inductance.

CAPACITOR:-

The capacitor's function is to store electricity, or electrical energy.

The capacitor is constructed with two electrode plates facing each other, but separated by an insulator.

When DC voltage is applied to the capacitor, an electric charge is stored on each electrode.

While the capacitor is charging up, current flows.

The current will stop flowing when the capacitor has fully charged.

LED:- A light-emitting diode (LED) is an electronic light source.

LEDs are used as indicator lamps in many kinds of electronics and increasingly for lighting.

LEDs are based on the semiconductor diode.

The longer lead is the Anode side and the short one is the Cathode side.

TEMPERATURE SENSOR:- The temperature sensor is known as the “Thermistor” A thermistor is an electronic component that exhibits a large

change in resistance with a change in its body temperature.

The word “Thermistor” is actually a contraction of the words “Thermal Resistor”.

DIODE:- A diode is a semiconductor device which allows current to flow through it in

only one direction.

Although a transistor is also a semiconductor device, it does not operate the way a diode does.

A diode is specifically made to allow current to flow through it in only one direction.

NTC THERMISTOR

The NTC thermistors are composed of metal oxides

The most commonly used oxides are those of manganese, nickel, cobalt, iron, copper and

titanium.

 A mixture of two or more metal oxide powders are combined with suitable binders, are formed to a desired geometry, dried and sintered at an elevated temperature

CIRCUIT DIAGRAM

BLOCK DAIGRAM

 

INPUT(220V AC)

Transformer

(220V/12V)

SENSOR(Themisto

r)RectifierAC to AC

OUTPUT(motor

rotating)Amplifier

WORKING The main intension is to control the fan by heating the sensor, i.e. the thermistor, where

the speed of the fan is dependent and controlled by any device’s temperature like PC. As the temperature of the device increases or decreases, the speed of fan increases or decreases respectively. So it can be used mainly as a cooling device. By modifying the circuit slightly, it can also be used to control the room temperature, depending on the property of thermistor.

The thermistor used in the circuit here, decreases its resistance with increasing temperature, hence the electrical conductivity also increases, increasing voltage across it, resulting in an increment in the speed of the fan. Thus, it is possible to control the speed of the fan automatically when the device’s temperature varies. Experiment can be followed to evaluate whether this circuit can save energy through the use of temperature sensor and thus promote efficiency.

ADVANTAGES:- This project can be used in Home.

This project can be used in Industry.

This will help in saving the energy / electricity.

To monitor the environments that is not comfortable, or possible, for humans to monitor, especially for extended periods of time.

Prevents waste of energy when it’s not hot enough for a fan to be needed.

To assist people who are disabled to adjust the fan speed automatically.

DISADVANTAGES:-

It can only be maintained by technical person. Thus, it becomes difficult to be maintained.

Due to temperature variation, after sometimes its efficiency may decrease.