What is Thermistor
Hello friends, I hope you all are doing great. In today’s tutorial, we will discuss
What is Thermistor. A thermistor is a semiconductor temperature sensing module, its value of the resistance is larger than the conductive substances and less than the insulators. The materials used for the construction of the thermistor defined the value of resistance and temperature of the thermistor. The producers of the thermistor make accurate relationship among temperature and their resistance because it is a very important factor for the users of the thermistor.
Oxides of the metals are used for the creation of the thermistors. During their manufacturing, the ratio of the resistance and temperature is defined accuratly because it is an important factor that defines the function of the thermistor. In today's post, we will have a look at working, manufacturing, and other different related parameters. So let's get started with
What is Thermistor.
What is Thermistor
- A thermistor is a resistor whose value of the resistance alters with the change of the temperature.
- The word thermistor is a combination of the two words first is thermal that means heat and second is resistance.
- In electrical circuits, the thermistors are used to stop the inrush current from the circuitries, as they are also sensors with the variation of the resistance they indicate about current.
- There are the 2 main categories of the thermistors first one is the NTC (negative temperature coefficient) and second is PTC (positive temperature coefficient).
- Negative temperature coefficient thermistor is such resistor whose resistance value falls with the increment of the temperature.
- NTC (Negative temperature coefficient) thermistors are mostly used for the resistance computations and to limit the value of the current in different circuitries.
- The positive temperature coefficients are such thermistors whose resistance value increases with the increment in the temperature.
- The PTC used in circuitries to provide protection against the overcurrent in the circuitries.
- These resistors are formed by crushing the oxides of the different metals using different methods for their creation.
- The main difference among the RTD (resistance temperature detector) and the thermistor is that RTD is manufactured by different metals while thermistors are formed by ceramic substances.
Working of Thermistor
- The resistance of the thermistor varies with the variation in the temperature. For calculation of the thermistor's resistance ohm-meter can be used.
- If we can find the accurate variation in the resistance of the thermistor with the variation in the temperature than we can easily find the value temperature by the resistance value.
- The material used for the creation of the thermistor defines how much variation will occur in the resistance.
- If we draw graphical representation among the resistance and the temperature than we will get the non-linear curve. It is shown in the given figure.
Construction of Thermistor
- For the production of the thermistor powder form of the 2 or more than the two oxides of metals blend to form paste-like arrangments.
- Then the different wires are inserted into this paste of metallic-oxides for the circuit connection, after that this composition is put into the oven for the removal of the water and to make it solid.
- After drying the paste solid obtained from the oven will be covered with the glass coating to provide protection from the moistures.
- In market numerous types, configurations and size of the thermistors are available.
- The smaller size thermistors have dia of 0.15 to 1.5 mm and their shape is similar to grains.
- These resistors are also available in the ring-like arrangements that formed during moulding of the thermistor that has dia of three mm to twenty-five mm.
- The resistance values that are used in a thermistor is one kilo-ohm, two kilo-ohms, ten kilo-ohms, etc.
Types of Thermistors
- There are two main types of the thermistors first one is the NTC (Negative Temperature Coefficient ) and the second one is PTC (Positive Temperature Coefficient).
- Let's discuss them with the detailed.
NTC thermistors
- This kind of thermistors is constructed by pressing the disc made by different semiconductors.
- When the temperature of these thermistors increases, the energy of the electrons of the material also increases, then they start to flow in the structure of the thermistor.
- The current due to movements of these electrons can be described in a given formula.
I = (n.A.v.e)
- In the above-given equation the 'I' is the current.
- 'n' is the no of the electrons.
- A is the area of the thermistor.
- 'v' is the speed of the electrons.
- 'e' is a charge of the electrons, its value is 1.602 10^-19.
- The current produced by the movement of the electrons can be found by the ammeter.
PTC Thermistor
- In this thermistors, the increment in the value temperature also increases the resistance and decrement in temperature will decrease the resistance.
- As NTC (Negative Temperature Coefficient) thermistors are commonly used but PTC is used for special circuitry like to provide protection. It also works as the replacement of the fuses.
- The operating temperature range for this thermistor is among the sixty Celcius and one twenty-degree Celcius.
- In special-cases its operating temperature can be zero to two hundred Celcius.
Comparison between Thermistor and Thermocouple
- Now we describe the differences between the thermistor and thermocouple with detailed.
Thermistors:
- The temperature measurement range for the thermistor is fifty-five celsius to plus one fifty-five celsius.
- It used for the measurement of the temperature.
- The thermistor shows the non- linear behaviour for the resistance and the temperature.
- In the case of the NTC (Negative Temperature Coefficient) the increment of the temperature will decrease the resistance.
- It can very easily assemble in the circuitries there is no need of special modification for the thermistor.
Thermocouples
- The operating range for the thermocouple is from minus two hundred to minus three-fifty for 'T' category, 'J' category temperature is ninety-five to seven sixty celsius, category 'k' has a temperature range from ninety-five to twelve sixty celsius.
- Its accuracy is higher.
- Its working principle is that it finds the value of the different at its terminals then find temperature using these voltages.
Applications of Thermistor
- These are some applications of the thermistors.
- The thermistor used for the calculations of the higher frequency energy signals.
- The thermal conductivity of the different substance can be found by the thermistor.
- It also used to calculate the composition of different gases.
- The pressure of the liquids can be calculated by the thermistors.
It is the detailed article on the thermistor if you have any question ask comments. Thanks for reading. Take care until the next tutorial.
What are Light Sensors
Hello friends, I hope you all are doing great. In today’s tutorial, we will have a look at
What are Light Sensors and how to use them. Light sensors are such components that sense the surrounding light and transform it into the current. Such sensors are normally used in different applications such as switching circuits and for security purpose. When they used in different security circuits these sensors detect the variation in the light then they send the signal to the alarm.
There are numerous types of light detectors components but there operating principle is similar. The most commonly used types of light sensors are a light-emitting diode, photodiodes, infrared radiation (IR) detectors, etc. In today's post, we will have a look at working, features, circuits, application and some other related terms so let's get started with
what are light sensors.
What are Light Sensors
- Such sensors that transform the light or infrared radiation into the electrical current are known as the light sensors.
- These sensors are also named as the photoelectrical detector, due to the conversion of the photons of the into the electrical energy.
- There are 2 main categories of the photosensors first one is that generates the electrical current when light collides with them are known as the photovoltaic sensors.
- The second one is that varies its electrical parameters like resistance are defined as the photoconductors.
- Such photo sensors that produce a voltage directly proportional to the amount of the light collided with them are known as photocells.
- There are such photosensors used in different circuitries to regulate the value of the current are known as photo junction modules. Such modules are used in different security circuits and electronic projects.
Photoconductive Cell
- This light detector module does not transform light into the electric current but the variation in its physical parameters occurs.
- The photoresistor is the example of these sensors when the light collided with this sensor varies the value of the resistance is also varied not light converted it to the current.
- Using this photosensor the value of the current is controlled in different circuits and engineering project, the normally used photoconductor is the light-dependent resistor (LDR).
Now we discuss it with detailed.
Light Dependent Resistance
- Light-dependent resistors are also known as the photoresistors, these light sensors are used in the different engineering projects to control the light strength for different components.
- It is constructed from the Cds (cadmium) this substance is very sensitive to light and according to the intensity of the light, it varies the value resistance.
- The working principle of the LDR is based on the photoconductivity, according to this the by an increase of the light the value of the conductive behaviour of materials increases.
- Light-dependent resistors modules are also called dependent device as its resistance varies according to light in the shadowy resistance is higher while in light resistance is less.
- In such region where light is not present LDR's resistance is known as dark resistance its value is up to the 1012 ohm.
What is the Light Dependent Resistor Cell
- The normally used type of the LDR cell is OPR12 it is manufactured by the cadmium sulphide. This sensor operates for such radiation that has six hundred nanometers wavelength of radiations.
- This sensor has large value of the resistance in shadow almost ten megaohms but in case of the light, its value is almost a hundred ohms.
- This cell is less expensive it mostly used in such devices that used at night in streets for illumination. In different cameras and photographic devices, it also used.
- If we connect this senor with the normal resistance and provide voltage to it than the circuit formed by this arrangments has benefits, that for different wavelengths of the light it produces different voltages. This circuit arrangement is shown in a given figure.
- The voltage drops across the series resistance R2 can find the voltage divider rule.
Photodiode
- The structure of the photodiode is alike to the normal diode, the only difference is that it has a coating of such material that absorbs the light.
- This coating absorbed mostly such lights that have less frequency than larger frequency.
- Light-emitting diodes are also recognized as the photo-diode because it can easily send and received light.
- When the light collides with the surface of the photodiode, hole and electrons pair are created in the module.
- Due to the formation of the hole and electrons current starts to flow in the diode.
- These pairs are created when the light collided with the diode has energy almost 1.1 electron volts.
- When the light energy collides the atoms than the electrons of the atom after gaining this energy left the atom and holes-electrons pairs are created.
- The charge on the electrons is negative and holes behave like positive charges.
- Due to the depletion regions, electrons and hole can not move from one part to other of the diode so electrons move towards the positive terminal of the diode and hole to the negative terminal.
Applications of Light sensors
- These are the main applications of the light sensors that are described with the detailed.
Brightness Control
- In our mobile phone and laptops, we increasing and decreasing the resolution of the screen light is varied by light sensors.
- Ambient sensors are mostly used in electronic devices like mobiles, laptops and computers.
- These sensors are also used in different street light for the automatic control of light.
Security System
- In different security circuits, light sensors are used. In shipping, these sensors provide protection for the different products that are moving from one place to another.
- Light sensors are installed in the cabin where the products are saved when someone tries to open the door light sensor sense slight and sends a signal to the alarm connected with it.
Agriculture
- The light of the sun plying the significant rule in agriculture for the production of the different crops.
- Different food seed requires a different quantity of light, so it is important to know which part of the land is under the sunlight.
- These sensors are used for the sprinkling of water when the sunlight is not available because most of the water will be converted into the moisture.
Sources
It is the detailed article on the light sensors if you have any question ask in comments. Thanks for reading. Take care until the next tutorial.
What are Position Sensors
Hello friends, I hope you all are doing great. In today’s tutorial, we will have a look at
What are Position Sensors and their practical implementation. Position sensors are such instruments used to detect the variation in the position of different components, or human beings. All movement controls networks comprise of such components that send information about the component or devices location connected with the network. These movement detectors are normally used in industries to control the operation of different machines.
Theses devices measure the complete variation in the position of the different tools or after some intervals of the time. These modules also have the ability to retains the data about the movements of a different tool, or machines. In today's post, we will have a look at different position sensors, their working, applications and some other parameters. So let's get started with
What are Position Sensors.
What are Position Sensors
- There are many types of position sensors are used in different engineering projects and industrial machines. Some are listed here, we will discuss all of them with detail.
- Potentiometer
- Linear Variable Differential Transformer
- Inductive Proximity Sensors
- Rotary Encoders
Potentiometer
- In almost every position detecting circuit or network, the potentiometer is used, due to its less cost, flexibility and easy to install features.
- It consists of the wiper like connected with the cars front screen, this wiper is linked with the shaft like different motors or generators, when the slider moves then its connection point resistance changes that convert into the electrical signal as an output.
- This resistance and the variation in the position of the slider are directly proportional to each other.
- These movement detectors are available in different structure and physical size, normally they are available in the cylindrical shape and flat structure.
- When they are installed in different circuitry the component whose motion to be detected is connected with the shaft of the potentiometer.
Linear Variable Differential Transformer
- As we are familiar with the transformer that used the phenomena of the mutual induction for its working.
- The linear variable differential transformer is and such position measurement module that transforms the smooth movement of any device into the current.
- Its construction is very simplest and can be installed in any condition and project.
- The most important part of this position sensor is a transformer and its core. The transformer has 3 windings one is on the primary side and the other 2 are on the secondary side. That is mention as S1 and S2 in the given figure.
- These two secondary windings are wound on the core that is made by the mixture of glass and polymers.
- These three windings are arranged in such a way that the 2 secondary windings are connected with the terminals of the primary windings that primary is in the centre and secondary windings are at left and right side of the primary.
- The other most important part of the linear variable differential transformer is the core that is manufactured by such material that has less resistance for the current movement.
- This core is linked with the non-conductive rod that acts as a shaft and this shaft is attached with the substance whose motion to be measured.
- The working principle of this sensor is that when the voltage provided to the primary side winding this voltage also induce voltage in the other secondary windings.
- The variation in the voltage values of the secondary windings indicates the distance covered by anybody connected with this sensor and angle between the voltages of the secondary windings tells about the direction followed by the substance.
Inductive Proximity Sensors
- This position sensor is also known as the eddy current sensor, and these components are not found position variation of anybody while they used to know the existing object near to it.
- These sensors are not connected physically with any other substance but they find the presence of any object by Faraday law.
- This sensor is consist of the core that is constructed by the ferromagnetic materials like iron and windings are wound around the core.
- When any conductive substance comes under the field of the inductive proximity sensor than the voltage induced in that substance is detected by the circuit of the sensor by this way he found the presence of any substance near it.
Rotary Encoders
- This position sensor has is similar to the potentiometer that we have discussed, but the difference is that potentiometer is to be connected with the device whose position to be measured but the rotary encoders find position without any connection.
- These sensors detect the movements of the substances and convert them into the electrical signal.
- These sensors are used light-emitting diode and disc that have different codes patterns that are mentioned in the binary system, decimal system or any other related system.
- When the disc moves its rotation is measured by the photo-detecting modules the rotation than converted into the electrical signal and this electrical signal that transformed to the binary numbers that send to the counter, in this way movement is measured.
Applications of the Position Sensors
- These are some important applications of the positions sensors.
- These sensors are used to find the angle of steering of automobiles and location of the gear.
- Clutch position can also st by this sensor.
- Industries the locations of different machine parts are found by using different position sensors.
- These sensors are also used in nuclear plants.
- In industries, it used for the different physical structure testing.
- Positions sensors not only used in industries but also installed in the medical instruments like magnetic imaging machine.
- In the different office, you have seen that the door is closed and open automatically these are controlled by the position sensors.
- To find the movement in the structure of the different bridges in position sensors are employed.
So that all about the position sensors, if you have any question ask in comments. Thanks for reading.
What is Diode Clipper?
Hello friends, I hope you all are doing great. In today’s tutorial, we will have a look at What is Diode Clipper and how to use it in rectification circuits. In different circuits especially in rectifiers, the clipper is used to maintain the predefined voltage level. These circuits do not interrupt the original signal but only control the variation in the predefined value of the signal. These circuits eliminate the variation in the original waveform at the positive half and negative half.
These circuits are created by the combination of linear components such as resistance and non-linear components like transistors and diodes. These clipping circuits are also known as the slicers. In today's post, we will also have a look at such circuits that are consists of diodes, their uses and their working. So let's get started with What is Diode Clipper.
What is Diode Clipper?
- The diode limiter is the other name for diode clipper circuits, these circuits reshape the input waveform by removing some part from positive half or negative half according to requirements.
- Diodes clipper circuits can be used for the modification of the input signal according to the load requirements, the most used diodes in these circuits are Schottky and Zener diode with the general diode.
- Such clipper circuits that comprise of the diodes are used as the voltage limiter in different engineering projects and instruments.
- As we are familiar with the working of the diode as rectifier it operates when its positive end is linked with the positive terminal of the battery and negative terminal with negative of battery but in case of opposite polarity it does not operates.
- The working of the diode clipper circuits is also similar to the rectification by the diode.
- Now we discuss the different circuits for the practical observation of the diode clipper circuits.
Positive Diode Clipping Circuit
- In the given below diagram, you can see that circuit one diode is connected to resistance and input supply in forwarding biasing conditions.
- The positive in the name of circuit suggest that this circuit will eliminate the positive cycle of the input signal.
- Due to forward biasing the diode will operate only in the positive half as the operating voltage for the diode is 0.7 volts so there will be only 0.7 voltage loss across resistance and other will convert into the dc.
- When the negative half comes on the diode it does not work and provides higher resistance like open switch resistance.
- In the given diagram you can observe this phenomenon.
Negative Clipping Circuit
- From the name of the circuit, we can conclude that it will eliminate the negative half of the input signal. It is shown in the given below circuit.
- When the positive half of the input signal comes on the terminals due to reverse biasing there is no change in the signal due to higher value resistance.
- When the negative half of the wave comes, in this case, the diode is forward biased, so the current will pass through it and the voltage drop across this diode will be 0.7 volts this is the voltage for the starting operation of the diode.
- In the given figure, you can see this process with the detailed.
Biased Diode Clipper
- This clipper circuit consists of an external voltage source with the diode in series for the cutting of the input supply.
- There are 2 main types of biased diode clipper circuits.
- Positive Biased Diode Clipper
- Negative Biased Diode Clipper
- Let's discuss these two in detail.
Positive Biased Diode Clipper
- In this kind of clipper circuit, some part of the positive half of the input signal is eliminated and there is no variation in the negative half of the signal.
- When the input voltage at positive is larger than the voltage source connected with the diode then the diode will cut the larger voltage and the output voltage will be equal to the biased voltage.
- During the negative cycle, there is no variation in the voltage and this cycle will be shown completely at the output.
- For example, if the voltage at the input is five volts and biasing voltage is two volts than the output voltage will be 2 volts other three voltage will be cut by this circuitry.
- It is because if the input voltage value is lesser than the voltage source (biased voltage) connected with the diode then behaves in reverse biased conditions and it will stop the biasing voltage flowing through the diode.
- If the value of the voltage is higher than the bias voltage diode is working in forwarding biased mode and the current start to pass through the load resistance.
Negative Biased Diode Clipper
- In this type of clipping circuit, some portion of the negative half of the input signal will be eliminated. And there will be no effect on the positive half of the wave.
- If the voltage at input has a positive value than the diode will be in the reverse-biased mode.
- So it will behave like an open circuit and all the voltage will be appearing across the output resistance.
- In the case of the negative half if the voltage is higher than the biased voltage the diode is now working in the forward biasing condition. And the exceded value will be removed from the waveform, the resultant waveform is drawn in the given figure.
Applications of the Diode Clippers
- These are some important applications of the diode clippers that are described here.
Reshape the Waveform:
- These circuits are used to vary the physical structure of the input wave according to our project requirements.
- By using these circuits the sine waveform can be changed into a square, rectangle or any other shape according to the circuit.
Circuit Transient Protection:
- Transient currents are very dangerous for any circuits that can damage our complete circuit, to stop all these transients current clipper diodes are also effective and can remove these transients.
It is a detailed article about diode clippers. If you have any questions ask in the comments. Thanks for reading. Take care until the next tutorial..