What is thermistor

Theory of thermistor:

Michael Faraday, the English scientist first discovered the concept of thermistor in 1833 while reporting on the semiconductor behaviour of silver sulfide. Through his research, he noticed that the silver sulfides resistance decreased as the temperature increased. This discovery would later lead to the commercial production of the thermistors in 1930 when Samuel Ruben invented the first commercial thermistor. Since then technology has improved paving the road to improved manufacturing processes along with the availability of higher quality material.


 Definition:

A thermistor is defined as a kind of resistor whose electrical resistance depends on varies with the changes in temperature. A thermistor is a temperature sensitive device. Basically, the thermistor is made of semiconductor materials that mean their resistance lies between the conductor and the insulator.


 Thermistor symbol:

The variation in the thermistor resistance shows that either conduction or maybe power dissipation occurs in the thermistor. The circuit diagram of thermistor uses the rectangular block which has a diagonal line on it.
thermistor symbol
Thermistor symbol
Types of  Thermistor:

The thermistor is classified into two types of based on how they behave with the change in temperature

  • Negative temperature coefficient temperature thermistor (NTC)
  • Positive temperature coefficient  temperature thermistor (PTC)
So now let us discuss these two types of the thermistor to better understand this topic:

Negative temperature coefficient thermistor (NTC): 

 In this type of thermistor the temperature increases with the decrease of the resistance. The resistance of the negative temperature coefficient thermistor is very large due to which it detects the small variation in the temperature.

Positive temperature coefficient thermistor (PTC): 

 The resistance of the thermistor increases with the increases in the temperature. 

Application for NTC and PTC thermistor include:
  • Temperature compensation 
  • Temperature control
  • Temperature measurement
  • Inrush current limiting

Benefits of NTC and PTC thermistors:

 NTC thermistor is basically rugged, stable, reliable and equipped more than other types of temperature sensors to handle extreme environmental conditions and noise immunity.
  • Compact size
  • Fast response time
  • Cost efficient
  • This thermistor was the ability to obtain a specific resistance at a particular temperature
Advantages and Disadvantages of thermistor:

 Advantages of thermistor:
  • It is a small size
  • Easy to use
  • They are fast in operation
  • It has good sensitivity in NTC region
  • Fast response over the narrow temperature range
  • Cost is low
  • Very responsive to changes in temperature
  • High accurate
  • Repeatable
  • Options for customization
  • Easily interfaced to electronics instrumentation

 Disadvantages of thermistor:
  • Thermistor need for shielding power lines
  • Extremely non-linear
  • Passive
  • More fragile as they are semiconductor devices
  • Susceptible to self-heating errors
  • The excitation for large temperature range
For detailed information:
Read  more >> Advantages and disadvantages of a thermistor

 You have also read:
Application of Thermistor:
  • It is used in automatic temperature controllers
  • It is widely used in temperature measurement
  • The thermistor measures the thermal conductivity
  • It is also used for biasing and compensating circuit of a transistor
  • In electronics circuit used for the temperature compensation
  • A thermistor is used in the control devices actuated by temperature
  • It is used the measurement of flow
  • It is used for the measurement of high-frequency power
  • It measures the composition of gases
  • It is used to measures the vacuum and provides the time delays
  • The thermistor measures the pressure of a liquid
  • Used for the thermal relay circuits and time delay circuit
  • It is used in the control devices actuated by temperature

What is thermocouple

History of thermocouple:

Thomas Johann Seebeck accidentally discovered the thermocouple in the year of 1821. He was experimentally determined that a voltage exists between the two ends of a conductor when the conductor's end is at different temperatures

Meaning of thermocouple:

The thermocouple is basically a temperature measuring device.  The thermocouple is used for measuring the temperature at one particular point. It issued to measure the temperature at one specific point or in the form of the EMF or in an electric current. The temperature can be measured at this junction and the change in temperature of the metal wire stimulates the voltage.

So the thermocouple is comprised of at least two metals joined together to form two junctions. One is connected to the body whose temperature is to be measured this is the hot or measuring junction and the other junction is connected to a body known as temperature. This is the cold or reference junction.  So, therefore, the thermocouple measures the unknown temperature of the body with reference to the known temperature of the other body.

Working principle of thermocouple:
  • See back effect: This type of effect occurs among two different metals. When the heat offers to any one of the wire, the electrons start flowing from hot metal to cold metal wire. Therefore the direct current induces in the circuit. In short this phenomenon in which the temperature difference between the two different metal induces the potential difference between them. The see back effect produces small voltage for per kelvin of temperature.
  • Peltier effect: This effect totally opposite to see back effect. This effect state that the difference of the temperature can be created between any two dissimilar conductors by applying the potential difference or variation between them. 
  • Thompson effect: This effect states that when two disparate metal fixed and join together and if they create two joints then the voltage induces the entire length of the conductor because of the temperature gradient. The temperature gradient is a physical term which shows the direction and rate of change of temperature at a particular location.

Construction of thermocouple:

  • Ungrounded junction: In this type of junction, the conductor is entirely isolated from the protecting cover. So this one can be used in high-pressure application work. The major benefits of using such type of junction are that it decreases the stray magnetic field effect.
  • Grounded junction: In this type of junction the metal wires and protective cover are welded together. The grounded junction use for measuring the temperature in the acidic atmosphere and provides resistance to the noise.
  • Exposed junction: The exposed junction is applicable in the area where fast response requires. This type of junction is used for measuring the temperature of the gas. The metal used to make the thermocouple basically depends on the calculating range of temperature.
Thermocouple junction
Thermocouple junction

Working of thermocouple:

The circuit of the thermocouple is shown in the figure given below. The circuit consists of two dissimilar metals. These metals are joined together in such a manner that they are creating two junctions. The metal is bonded to the junction through welding

Let shown that in figure P and Q are two junctions of the thermocouple. The T1 and T2  are the temperatures at the junctions. As the temperature of the junction is different from each other, the EMF generated in the circuit 

If the temperature at the junction becomes equal, the equal and opposite EMF  generate in the circuit, and the zero current flows through it. If the temperature of the junction becomes unequal, the potential difference induces the circuit. The total current flowing through the circuit is measured through the measuring devices

Iron constant thermocouple
Iron constant thermocouple

The electromagnetic force induced in the circuit is calculated by the following equation
E = a (Δ𝛉) + b (Δ𝛉 ) 2
Where  Δ𝛉  is the temperature difference among the hot thermocouple junction end as well as the reference thermocouple junction end and here a and b are constant.  
Advantages  and disadvantages of thermocouple:

 Advantages or benefits of thermocouple:
  • Fast response time
  • They are a simple construction
  • Low initial cost
  • Durable
  • Not required bridge circuit
  • Good accuracy
  • Does not required bridge circuit
  • Good reproducibility
  • High-speed response
  • They are rugged
  • They are a self-power active device
Disadvantages  or drawback of thermocouple:
  • Not as stable as RTD
  • Recalibration is difficult
  • More susceptible to RFI/EMI
  • Less sensitivity
  • They require a reference for operation
    The stray voltage pick up is possible
For detailed information :

 You have also read:
1. RTD - Advantages and Disadvantages
2. Thermistor - Advantages and Disadvantages

Thermocouple applications:
  • These are used in gas machines for detecting the pilot flame
  • These are used to test temperature in the chemical plants, petroleum plants
  • These are used in the food industry for cryogenic and low-temperature application
  • These are used for a heat pump for performing thermoelectric cooling
  • These are used for medical equipment
  • It can be used for packing equipment
  • It can be used as Diesel engine
  • These are also used for plastic industry modeling machinery, steel industry
For detailed information
Read more >> Application of thermocouple

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Difference between amplifier and repeater

Amplifier and repeater are basically two types of electronic circuits used in a communication system. Usually, the communication happens between two points through a wired as well as wireless system. Basically, the transmitter sends a signal containing some information and traveling some distance, usually, a signal gets weekended due to energy loss in the medium. The amplifier is the circuit which magnifies the weak signal to signal with more power. Sometimes this signal attenuation happens much before the arrival to the destination. In this case, the signal is amplified and retransmitted with power gain in one or more midpoints. Those points are called as a repeater. So, therefore, an amplifier is an essential part of a repeater.

Definition of amplifier and repeater :
  • The amplifier is an electronics circuit that increases the power of an input signal. There are many types of amplifier ranging from voice amplifiers to optical amplifiers at different frequencies. A transistor can be configured as a simple amplifier. 
  • The repeater is an electronic circuit that receives a signal and retransmits the same signal with high power. Different types of repeaters have different types of configurations depending on the which type of transmission medium. If the medium is optical it may contain photodetector and light emitters and if the medium is microwave repeater may consist of antenna and waveguides.
The main key difference between amplifier and repeater are listed below:
  • Amplifier just increases the amplitude of the signal while the repeater is decoded the signal and extract the original signal and regenerate the signal the retransmit it.
  • The amplifier is a low gain and high output power, the repeater is high gain and low output power.
  • A repeater has an amplifier as a part of it.
  • The amplifier amplifies the signal along with the noise while in repeater eliminates the noise by regenerating the signal.
  • The amplifier is mainly used in a remote area and mobile environment, whereases repeaters is mainly used in a stationary environment.
  • The amplifier has minimized the signal to noise levels, therefore, increases the noise while repeaters maximize the signal to noise ratio hence decreases the error associated with the signal.

Difference between active and passive filter

The filter is one type of circuit which changes amplitude and phase of the input signal and produces output. The filters eliminate some frequencies and pass some frequencies hence it provides different attenuation to different frequencies. Based on components used in the construction of the filter there are two types of filters one is active filter and other is a passive filter. 

 What is an active filter? 

 The active filter uses active components such as operational amplifier addition to resistors and capacitors in the construction of the filter. 

 What is a passive filter? 

 The passive filter uses passive components such as resistor, coils or inductors and condenser or capacitors in the construction of the filter. 

 Active filters require an external power supply while we are using passive filter operate only on the signal input. Here this article gives information about the active filter vs passive filter to better understand this topic.

 Main difference :

 The main difference between active and passive filter is that passive filters can't cause a power gain or can't bring energy into circuit whereas active filter can add energy into the circuit and also control current. 

 Difference :
  • The active filter requires an external power supply while passive filters operate only on the signal input.
  • A passive filter is constructed using only passive components while active filters may contain active as well as passive components.
  • The active filter uses elements like op-amps and transistor which are active filter elements.
  • Passive filters have no frequency limitations while active filters have a limitation due to active elements.
  • Only passive filters use inductors.
  • Passive filters consume the energy of the signal, but not power gain is available while active filters have a power gain.
  • Passive filter has no external power source, active filters require an external power source.
  • Passive filters are relatively cheaper than active filters.
  • The passive filter has better stability and can withstand large currents.
  • The passive filter may consist of inductors, active filter do not contain inductors.
  • Compared to active filters properties of passive filters may change significantly when the load it must be changed.
  • Passive filters can be used at high frequencies by using inductors, while in active filters the frequency range is dependent on the bandwidth of the amplifier typically to filter high-frequency signals, passive filters are used.
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Advantages and disadvantages of passive filters

Filtering circuits are more important to many electronics designs because they remove unwanted frequencies. They are popular form because they do not need a power supply and depend on passive components rather than active components. This post gives information about the advantages and disadvantages of passive filters to better understand this topic.

Advantages of passive filters:

  • It is reliable
  • They can handle large voltage currents and power
  • There is no limitation on the frequency range
  • They do not need the additional dc power supply for their operation
  • Easy to design
  • Cheaper as compared to active filter
  • No amplifying elements
  • Require no power supply
  • High frequency

Disadvantages of passive filters:

  • Response problems
  • Tuning for fixed frequency
  • Fixed reactive power compensation
  • Large in size
  • There is no isolation between input and output
  • The circuit becomes bulky if inductors are used
  • There is always some loss of signal it can be in the passband
  • This circuit can not provide any gain
  • Source loading can take place
  • There is no clear demarcation between passband and stopband but actually, it gets mixed up
  • In this frequency response is not sharp since when switching from passband to stopband there is no sudden change in output.
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Advantages and disadvantages of active filters

An active filter is a group of electronics filters that will utilize active components like an amplifier for its functioning. This article gives information about the pros and cons of active filters to better understand this topic.

Advantages of active filters:
  • These filters are more responsible than passive filters
  • No resonance issue
  • It can eliminate any harmonics
  • Used for voltage regulation
  • Used for reactive power compensation
  • It provides reliable operation
  • It can be designed to provide some passband gain
  • No loading problem
  • Active filter using OP-AMP does not load the input load
  • It does not exhibit any insertion loss
  • It also allows for isolation control of input and output impedance
  • The component used in the active filter is the smaller size as compared to passive filter
Disadvantages of active filters:
  • It is expensive
  • It provides a complex control system
  • The active filter is only suitable for low or moderate frequencies
  • It can not handle a large amount of power
  • It requires DC power supply for their operation
  • This filter is limited in their frequency range

Difference between thermistor and thermocouple

Thermistor has used to measure the small temperature. It has lead whose resistance reduces their accuracy. It can detect even small variation in temperature while in thermocouple are used for measuring the temperature of large industries. It is less costly and more accurate. In this article, we can check it out thermistor vs thermocouple to know more about it. Let you first learn the definition of thermistor and thermocouple.

Definition of thermistor and thermocouple :
  • A thermistor is the type of thermal resistor whose resistance changes with the temperature. It is made of semiconductor materials. Thermistor uses the temperature coefficient shows between the variation in the value of resistance and the temperature. While uses thermistor has two types of temperature coefficient positive and negative.
  • The thermocouple is a temperature measuring device while using thermocouple the two wires of different metals are connected at one point. When the two dissimilar metals induce a voltage because of the variation in temperature of the metals. 
A main key difference between thermistor and thermocouple listed below:
  • A thermistor is a type of thermal resistor while thermocouple is the temperature measuring devices.
  • Thermistor has linear characteristics, while thermocouple nonlinear characteristics for negative temperature coefficient.
  • Thermistor has lead whose resistance reduces their accuracy but thermocouple has high accuracy as compared to the thermistor.
  • A thermistor is made by the semiconductor or by the oxide of magnesium. nickel or cobalt while thermocouple is made from metal or alloys of metals.
  • Thermocouple and thermistor both are used for controlling and measuring temperature.
  • A thermistor is used in home applications while thermistor is used in large industries.
  • Thermistor requires the external power source, the thermocouple is less expensive as compared to the thermistor.
  • Thermistor measuring range of -50-degree Celsius to 250 degree Celsius whereas that of the thermocouple is -200 degree Celsius to 1250 degree Celsius.
  • Thermistor gives a quick response as compared to the thermocouples.
  • In thermocouple the variation in temperature is determined by the voltage induces at their junction. While the resistance of the thermistor changes when their surrounding temperature must be varied.

Difference between amplifier and oscillator

An amplifier is an electronic circuit providing output as an amplified form and an oscillator is an electronic circuit providing output without input application. There is no periodic signal generated by the amplifier.

 Main Difference :

 The main key difference between amplifier and oscillator is that amplifier is an electronic device that is used to increase the amplitude of electrical signal but in the oscillator is an electric device that is used to generate oscillatory electric current or voltage by no mechanical means.


amplifier vs oscillator


Difference between amplifier and oscillator is listed below:
  • The amplifier is an electronics circuit which gives output as an amplified form of input while in the oscillator is an electronic circuit which gives output without application of input.
  • The amplifier is basically negative feedback but oscillator uses positive feedback.
  • The amplifier does not produce any signal but oscillator are built to generate electronic signals.
  • Amplifier operates as a muliplier, oscillator oprate as a souce.
  • The amplifier provides an amplified signal, the oscillator is given the oscillatory signal.
  • The amplifier does not generate any periodic signal but the oscillator is generating of the periodic electronic signal.
  • Amplifiers do nothing till input signal is fed to the input, oscillator produces a signal from the moment of power.
  • The amplifier has both input and output while oscillators only have an output.
  • An oscillator generates a signal with a specific type of frequency so an oscillator itself uses an amplifier in order to generate a strong signal.
  • An Amplifier accepts an as input signal and produces a basically output signal which is an amplified version of the input signal.
  • In amplifier phase shift between input and output generally in between 180 degrees while the oscillator phase shift between input and output is 0 degree or 360 degrees.
  • In an amplifier, output frequency depends on active as well as the passive component used, while oscillator output frequency depends on only passive components.

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Difference between series circuit and parallel circuit

There are many ways to set up an electrical circuit. Electronics devices such as resistors, transistors, switches, diode, are components place and positioned in a circuit structure. The placement of such components is crucial to the operation of the circuits because different kinds of setup create a different kind of output or results. Two of the simplest electronics or electrical circuit connections are called a series and parallel circuits. These two are the most basic setup of all circuits, but significantly different from each other.


 Series circuits :

Generally, a series circuit has the same amount of current flow through all the components placed inline called the series because of the fact that the components are in the same single path of the current flow. 

In series circuits : 

Vt = V1 + V2 + V3 +........

It = I1 =I2 = I3 =.......

Rt = R1 + R2 + R3 +.......

Where, Vt = Total circuit voltage

V1, V2 and V3 = Voltage in each component
It = Total current
I1, I2, I3 = Current across each components 
Rt = Total resistance
R1 = R2 = R3 = Resistance value of each components


Parallel circuits : 

Generally, the parallel circuit has the same amount of voltage flow through all the components placed parallel called parallel circuits. The components are wired in separate loops. This circuit divides the current flow and ultimately combines the current flowing through each component to form the current flowing in the source.

In parallel circuits :

Vt = V1 = V2 =V3.....

It = V ( 1/R1 + 1/R2 + 1/R3 ).....

1/Rt = 1/R1 + 1/R2 + 1/R3 +......


Main Difference : 

In a series circuits, the same amount of current flow through each of the components, and the voltage across the circuit is also the same of the voltages across each component. The voltage across each component is the same in a parallel circuit, and the total current is the sum of the currents across each component.

Now let we check it out some other difference between them one by one listed below. 


Difference :

  • Series circuit is an element we said to be connected if they are connected in cascade fashion called end to end, one after the other. If the finish point of the one element is connected to the start point of the next element and so on just like the links in the chain  while in parallel the element is said to be connected in  parallel if they are connected across each other one end of each element is bunched together to form one junction and the remaining end of each element is bunched together to form one junction and the remaining end of each element is bunched together to form the other junction. 
  • Each resistor in the circuit is not directly connected to supply in series circuits while in parallel circuits resistors are connected in end to end and directly connected to supply. 
  • There is only one path through which current flow in series circuits whereas in parallel circuits, the current is divided because there are many paths through which current flows. 
  • In the series circuits, the sum of the total voltage drop across resistors is equal to emf source whereas the current supply by the battery is equal to the sum of all current flow across each resistor in the circuit in parallel circuits. 
  • The value of equivalent resistance is larger than the value of the largest resistor connected in series circuits in case of a series circuit and the value of equivalent resistance is lesser than the value of smallest resistors connected in parallel circuits. 
  • If any resistor burns out in the series whole circuits will be disconnected from the supply while the current is not interrupted in parallel circuits if any resistor damage.

Full form of PLC

What is the full form of PLC?

  • Programmable Logic Controller

 What does PLC mean?


A PLC is microprocessor-based an industrial digital computer which has been ruggedized and adapted for the control of manufacturing processes, automation of the electromechanical process, such as lines, robotics devices, light fixtures or any activity that require high-reliability control and ease of programming process. So this system will work by monitoring the state of input devices and it makes decisions based upon a basic custom program to control the state of output devices.

Advantages and disadvantages of integrated circuits

Integrated circuit (IC), sometimes called as a chip or microchip that can work as an amplifier, oscillator, timer, microprocessor, or even memory of a computer. An IC is a small wafer, usually made of silicon, can be a function as an amplifier, oscillator, timer, counter, computer memory, or microprocessor. This post gives information about the pros and cons of integrated circuits called ICs to better understand this topic.

Advantages of ICs:
  • It is more reliable
  • The entire physical size of IC is the extremely small size
  • Low power consumption because of their small size
  • It can easily replace but it can hardly remain in case of failure
  • It has suitable for small signal operation
  • Greater ability to operate at extreme temperature
  • When the absence of parasitic and capacitance effect has an increased operating speed
  • The wight of an IC is very less as compared entire discrete circuits
  • Close matching of components and also a temperature coefficient because of bulk production in batches
  • Improved functional performance as some complex circuits can be fabricated for achieving better characteristics
  • The reduction in power consumption is achieved due to the extremely small size of IC

Disadvantages of ICs:
  • If one component in an integrated circuits fails, it means the whole circuit has to be replaced
  • It is difficult to be achieved low-temperature coefficient
  • It can be handled an only a limited amount of power
  • Coils or indicators cannot be fabricated
  • Low noise and high voltage operation are not easily obtained
  • The power dissipation is limited to 10 watts
  • Inductors cannot be fabricated directly
  • High-grade P-N-P assembly low-temperature coefficient
  • Operation at low voltage as IC function at fairly low voltage
  • Voltage dependence of resistor and capacitors
  • A large value of saturation resistance of transistors
  • Integrated circuits are not flexible
  • It is impossible to fabricate transformers
  • The IC will not work properly if wrongly handled or  it must be exposed to excessive heat
  • The power that integrated circuits can produce is limited and calls for extension
  • Higher values of capacitance discrete components exterior to the IC chip are connected

Advantages and disadvantages of PLC

PLC called a programmable logic controller, it has specially designed computer to operate in an industrial environment, which can operate in a wide range of temperature and humidity. Here this post gives a lot of advantages and disadvantages of PLC to better understood this topic. 

Advantages of PLC:
  • Rugged and designed to withstand vibrations, temperature, humidity and noise
  • PLC has a lot of contacts and low cost and safe
  • It has a very faster scan time, it has a fast operating time
  • A wide range of control application
  • It has capable to communicate with a computer in the plant
  • It has great computational capabilities 
  • It has shorter training time required
  • It has a small physical size
  • It has project cost can be accurately calculated
  • It has supervisory control capability
  • PLCs are easily programmed and it was relatively easily understood programming language
  • Have interfacing for input and output already inside the controller
  • One single programmable logic controller can easily run many machines so it is flexible
  • It has high-speed counters
  • It has shorter project implementation time
  • Troubleshooting in programming and reprogramming
  • The documentation was easy to do
  • It has a high level of reliability and low maintenance
  • Security in terms of programming
  • Adaptive to changes in production

Disadvantages of PLC:
  • There is too much work required in connecting wires
  • It has fixed circuit operation
  • PLCs manufacturers offer only closed-loop architecture
  • PLC is new technology so that should require training
  • There is a limitation of working of PLCs under high temperature, vibrations conditions
  • Some PLCs turn on when power is restored and may cause an accident
  • There is a difficulty with changes or replacement
  • Need extra security equipment such as really
  • Some application that performs a single function is not efficient in the use of PLC
  • Limited usage environments high temperatures and harsh vibrations can disrupt electronic equipment on the PLC
  • PLC is not considered necessary when it has applied to industrial systems that do not need to change the wiring
  • PLC is designed by semiconductors, which depends on the thermal characteristics
  • It is always difficult to find an error and requires a skillful workforce
  • When uses PLC, a problem occurs hold up time is indefinite and usually long
  • A number of operational modules must be added to maximize flexibility and performance
  • PLCs are propitiatory, meaning that the software and the use of parts can't be easily used by one manufacturer in combination with some uses by another manufacturer.
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Difference between synchronous and asynchronous transmission

The main key difference between synchronous and asynchronous data transmission is that while we are using synchronous transmission uses synchronized clocks to transmit data while in asynchronous transmission uses flow control instead of using a synchronized clock to the transmit data.

  • In synchronous transmission, data is sent in the form of block or frames but in the asynchronous transmission, data is sent one byte or one characteristic at a time.
  • In synchronous transmission, the rate of transmission of data is fast while in asynchronous the rate of transmission of data is slow.
  • Synchronous transmission is expensive, Asynchronous transmission is economical.
  • In synchronous time interval constant, while in asynchronous time interval random.
  • The gap between the data is absent but while in an asynchronous gap between the data is present.
  • Synchronous example chat room, video conferencing,  face to face interaction, telephonic conversion, etc but in an asynchronous letter, emails, forums, etc.

Advantages and disadvantages of negative feedback amplifiers

Negative feedback amplifier has effects for reducing distortion, as well as noise, form sensitivity to external changes and improving system bandwidth and input and output impedances. Here this post gives some advantages and disadvantages of negative feedback amplifier over the positive feedback amplifier to better understand this topic.

Advantages of a negative feedback amplifier:
  • The negative feedback reduces the size
  • It has highly stabilized gain
  • It has fewer harmonics distortion
  • It has less phase distortion
  • It has higher fidelity
  • More linear operation
  • It has less frequency distortion
  • Input-output impedances can be modified as desired
  • It can increase or decrease output impedances
  • It can control the step response of an amplifier
  • It can control the step response of an amplifier
  • It has less amplitude distortion
Disadvantages of a negative feedback amplifier:
  • Its reduction in gain
  • It increases output resistance in the case of shunt and current series feedback amplifiers
This article also gives some advantages and disadvantages of a negative feedback amplifier over a positive feedback amplifier:

Advantages of a negative feedback amplifier over a positive feedback amplifier:
  • The operating point is stabilized
  • Output resistance decreases for certain configurations
  • Input resistance increases for certain configuration
  • The negative feedback is employed in various application such as an electronic amplifier, regulated power supplies, wideband amplifier, etc
Disadvantages of negative feedback over the positive feedback amplifier:
  • It reduced gain
  • Reduction of input resistance for current shunt amplifiers and voltage shunt type
  • Increases in output resistance in case of current series and current shunt feedback amplifiers
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Difference between scr and triac

The main difference between the two is that silicon control rectifier (SCR) switch direct current while in TRIAC is switch is alternating current. Here this post gives the main difference between them.
  • SCR stands for silicon controlled rectifier while TRIAC stands for triode for alternating current.
  • SCR is a unidirectional device but the TRIAC is a bidirectional device.
  • SCR is available in large rating but TRIAC is available for smaller ratings.
  • SCR is more reliable compared to TRIAC.
  • SCR is conducting current in one direction only while TRIAC is conducting current in both directions.
  • SCR need two heat sink, TRIAC needs only one heat sink.
  • SCR is only one mode of operation is possible whereas in TRIAC four different modes of operation are possible.
  • SCR can be triggered by positive gate voltage only but TRIAC can be triggered either by both positive or negative gate voltage.
  • SCR control a DC power, TRIAC control DC as well as AC power.
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Thermocouple application

There is some application of thermocouple listed below:
  • These are used as the temperature sensors in offices, homes, offices, and businesses
  • These are in industries for monitoring temperatures of metals in iron, aluminium, and metal
  • These are used in gas machines for detecting the pilot flame
  • These are used to test temperature in the chemical plants, petroleum plants
  • These are used in the food industry for cryogenic and low-temperature application
  • These are used for a heat pump for performing thermoelectric cooling
  • These are used for medical equipment
  • It can be used for packing equipment
  • It can be used as Diesel engine
  • These are also used for plastic industry modelling machinery, steel industry
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