The Engineering Projects

Introduction to 2sc4617

Hey Fellas! Hope you are doing great. I am here to give you the daily dose of information relating to engineering and technology. Today, I am going to give you the details on the Introduction to 2sc4617. It is an NPN (negative-positive-negative) transistor which is used for general purpose amplification. This component comes in SC-75/SOT-416 sealed package which is mostly used for low power applications. I am going to explain the brief overview of 2sc4617. Let's get started.

Introduction to 2sc4617

• 2sc4617 is a three terminal NPN silicon transistor which consists of two N doped layers which cover one P doped layer. It is a bipolar transistor which is usually used for amplification purpose.
• Small amount of base current is used to handle the large current on the emitter and collector side.
• Supply voltage at collector is positive with respect to emitter.
• Free movements of electrons from its base side is used to control the current between emitter and collector.
• This device comes in a compact form, that it reduces the space to put all device in one place.
• Most of the old transistors were made of germanium. New transistor are made up of silicon.
• In the ON state of the transistor, current will flow from emitter to collector.
• The voltage between collector and base is 50 V and is denoted by Vcb.

• The voltage between collector and emitter is also 50V and is denoted by Vce.
• Collector current is 100mA and is denoted by Ic.
• Maximum power dissipation is 125 mW.
• Whole device comes in a sealed form and is placed on the glass epoxy printed circuit.

2sc4617 Pinout

Pinout of 2sc4617 silicon transistor is shown in the figure below. This transistor consists of three terminals. 1: Base 2: Emitter 3: Collector

• Transistor 2sc4617 is also known as current operated device.
• It is mainly used for amplification purpose.
• The way base current effects the emitter and collector current is used for amplification purpose.

 

Circuit Symbol of 2sc4617

Circuit symbol of 2sc4617 is shown in the figure given below.

• 2sc4617 is an NPN transistor, and it will source the base current to the transistor.
• Base of the transistor is more positive than emitter.
• Current at the emitter side is equal to the sum of current at the base and collector side.
• The measure of number of electrons that pass from base to collector is called transistor efficiency.
• Base is lightly doped and emitter is heavily doped that will allow the electron to move from emitter to base more than it will allow the holes from base to emitter.
• Ratio between collector current and base current is called forward current gain. It has a standard value of 200.
• Forward current gain is represented by beta ß.
• Value of beta ranges between 20 to 1000.
• Ratio between collector current to the emitter current is called current gain of the transistor and it is denoted by alpha a.
• Value of alpha ranges between 0.95 to 0.99. However, most of the cases value of alpha is considered as unity.
• Transistors are always operate in forward biased mode. If we interchange emitter and collector and makes it reverse biased, then the value of alpha and beta will be much lesser than they will be in forward biased mode.
• This NPN transistor  has low impedance at the base side.

Maximum Rating of 2sc4617

Maximum current and voltage rating of 2sc4617 is given in the figure below.

• The voltage between collector and base is 50 V and the voltage between collector and emitter is also 50V.
• Collector current is 100mA and is denoted by Ic.
• Rating given above, if increased from given limits, can damage the device at large.

Thermal Characteristics of 2sc4617

Thermal features of this bipolar transistor is given below.

• Power dissipation is 125mW.
• These thermal characteristics are  important for tuning your circuit requirements.

Electrical Characteristics of 2sc4617

Electrical characteristics are of great value. They are shown in the figure below.  

• It is important to note that, these electrical characteristics don't indicate the overall performance of this device.
• These electrical characteristics are measured at the temperature of 25 ºC

Applications

• 2sc4617  is mostly used in coin processing machines.
• They are widely used in PLC (programmable logic controllers)
• Used for controlling DC and servo motors
• Used for general purpose amplification.

That's all for today. I have tried my best to explain each and everything regarding this 2sc4617 transistor. However, if you still find any difficulty in understanding the concept of this transistor, you can ask me in the comment section below. I'll be happy to help you in this regard. Thanks for reading the article. Stay tuned for next article. Good Bye!

Introduction to 2n4391

Hey everyone! Hope you all are doing great. Today, I am going to give you the details on the Introduction to 2n4391. It is a simple N type JFET (Junction field effect transistor) which consists of three terminals called drain, source and gate and are denoted by D, S and G receptively. It is mostly used in analog switches and current limiters. I am going to give you a brief details on this transistor. Let's get started.

Introduction to 2n4391

• 2n4391 is a field effect transistor that consists of three terminals known as drain, source and gate.
• It is called field effect transistors because static field performs as important part in the operation of this transistor.
• Unlike normal transistors, it is a voltage controlled device as it doesn't require any biasing current to control large amount of current.
• It conducts, when current flows between drain and source terminals.
• A JFET is considered fully ON as long as no potential difference appears between source and gate terminals. Similarly, applying a negative gate-source voltage will turn off JFET.
• It restricts the flow of current if there appears any potential difference between source and gate terminals.

• A JFET comes in two types, N type and P type channel. 2n4391 is a N type JFET where voltage at the source terminal is greater than the voltage at gate terminal.
• 2n4391 is composed of semiconductor material which contains negative charge carriers such as electrons.
• In JFET, the flow of current is handled by limiting the channel through which current is flowing.
• Current also has a large effect on the electric field between drain and source.
• 2n4391 comes with high speed analog circuit performance and low error voltage.
• It has excellent accuracy, good frequency response that eliminates the additional buffering.

2n4391 Pinout

Pinout of field effect transistor 2n4391 is shown in the figure given below: 2n4391 consists of three terminals 1: Drain  2: Source 3: Gate

• It will conduct when current flows between drain and source terminals.
• In this N type FET voltage at the gate terminal is used to handle the current flowing through the device.

Working of 2n4391

• Movement of election plays an important role in the operation of all transistors.
• Conducting channel in this N type JEFT is made by field effect process.

 

• In N-type JFET, flow of electrons between source and drain is restricted by the number of holes in the gate terminal.
• However, an electric filed is generated when we apply positive voltage at the gate terminal. It results in the flow of electrons from source to drain terminal, that ultimately switches on the transistor.

 

• Current is generated by the addition of "field effect", that's why these transistors are named as field effect transistors.
• Coating silicon layers with metal oxide gives this component a different name called MOSFET ( Metal Oxide Semiconductor Field Effect Transistor).

 

Absolute Maximum Ratings of 2n4391

Absolute maximum ratings of this N type JFET is given in the figure below.

• Gate-Drain and Gate-Source voltage is -40V.
• Gate current is 10mA.
• It is important to note that ratings more than given on the above table can damage the device at large.
• These are the stress rating that can be implied duration the operation of this JFET.
• Similarly, if these rating are implied more than given time period, they can effect the reliability of device.

Comparison between JFET and Bipolar Junction Transistors

• JFET are like normal transistors with some exceptions. In case of JFET, layers of N-type silicon material are coated with metal and oxide and they are placed in a different way than normal transistors.
• Normal junction transistors are bipolar transistors i.e. they will conduct by the movement of electrons and holes in transistors.
• JFET are uni-polar transistors, i.e. they either conduct with the movement of electron in N type transistors or movement of holes in P type transistors.
• Both junction transistors and JFET come with great accuracy, show instant operation and both are robust and cheap.
• However, in most of the electronic application JFET evidently replace bipolar transistors.

Applications

• It is a good choice for specialized amplifier circuits and analog switching application.
• It is mostly used in commutators and choppers.

That's all for today. I hope you have got a clear idea of this N type JFET. However, if still you feel any doubt or have any question regarding this FET, I'd glad to help you in this regard. Your suggestions and feedbacks will be highly appreciated. Stay tuned!

Introduction to 2sa1215

Hey Everyone! I hope you all are having fun and looking forward for happy weekend. I am here to give you a daily dose of sound knowledge so you can develop some skills in engineering field. Today, I am going to uncover the details on the Introduction to 2sa1215. It is bipolar silicon PNP (positive-negative-positive) transistor. It is made up of two layers of P doped material and one layer of N doped material. I'll give you the brief overview of this device, what it does and what are its major applications? Let's hop on the board and dive into the details of this PNP transistor.

Introduction to 2sa1215

• 2sa1215 is a bipolar PNP silicon transistor where one layer of N doped material lies between the two layers of P doped material.
• The small current at the base side is used to handle the large current at the emitter and collector side.
• In PNP transistor, P side represents the polarity of voltage at the emitter side which is positive and N represents the polarity of base side which is negative. In PNP transistor, Emitter is always positive with respect to base.

• 2sa1215 has a current gain that ranges between 50 to 180.
• Some people get deceived by the dust like surface on this transistor, which actually is not a dust, but an anti-static powder.
• It is also called high frequency multi emitter transistor.

2sa1215 Pinout

Pinout of 2sa1215 is shown in the figure below. 2sa1215 consists of three terminals 1: Base 2: Collector 3: Emitter

• Current will flow from collector to emitter and current carries are holes.
• Sometimes 2s prefix is not written on the component. 2sa1215 can be written as A1215.
• 2sc2921 is the complementary NPN transistor of 2sa1215.
• 2sa1215 can be replaced by 2sa1493, or 2sa1216

Circuit Symbol 2s1215

Circuit symbol of 2s1215 is shown in the figure below. It is made up of two P layers and one N layer.

• Polarity at the emitter side is positive as compared to base and collector.
• Base comes with negative polarity with respect to emitter.
• Small current at the base side is used to handle the large current at the collector and emitter.
• PNP also works similar to NPN, but in case of PNP current direction will be reversed and current carriers used in case of PNP will be holes rather than electrons that are current carriers in NPN transistors.
• Current at the emitter side is equal to the sum of current at base and collector side.

Maximum Rating of 2sa1215

Maximum rating of 2sa1215 is shown in the figure below.  

• Collector base voltage is 160 V and is denoted by Vcb.
• Collector emitter voltage is also 160 and is denoted by Vce.
• Power dissipation of this transistor is 150W.
• Collector current and base current are 15 A and 4 A repectively.
• Transition frequency is 50MHZ.

 

How to Identify Genuine 2s1215

There are genuine and fake (Chinese) transistors out there. However, you don't need to worry about that, I am going to give you three ways by which you can check if transistor is genuine of fake.

• 1: Genuine copy of transistor 2s1215 comes with a weight of 18.4g, which its Chinese copy only weighs 15.7g.
• 2: Genuine copy consists of two layer metal heat sink, while Chinese copy only consists of one layer metal heat sink.
• 3: Transistors can also be classified on the basis of their output. Genuine copy gives good output, while in case of Chinese copy, output is broken.

Difference between NPN and PNP transistors

• Both NPN and PNP transistors works in a similar way with the exception that Base is positive in case of NPN transistor and is negative in case of PNP transistor. NPN transistor sources the current from its base to the transistor while in case of PNP it sinks the current into its base side.
• NPN and PNP are also different with respect to medium used to carry current. Current carriers in NPN transistors are electrons while current carries are holes in case of PNP transistors. Holes are collected by the collector.

Applications

• It can be used for high audio output stage.
• It is also used as general purpose amplifier and for switching applications.

That's all for today. I hope you have got an idea of this PNP transistor. If you have any question you can ask me in the comment section below. I'll try my best to resolve your query as soon as possible. Thanks for reading the article. Get ready for next article. Till then, stay happy and blessed. Good Bye!

Introduction to 5n50

Hey Everyone! I hope you are doing great. I am back to give you daily dose of information so you can excel in your life. Today, I am going to uncover the details on the Introduction to 5n50. It is an N-Channel MOSFET which is designed to obtain high switching performance and minimum on state resistance in an effective way. It is a unipolar device which comes with three terminals called drain gate and source. I'll try to cover everything in detail related to this N-Channel MOSFET. Let's hop on the board and dive in the details to unlock the features of this transistor.

Introduction to 5n50

• 5n50 is an N-Channel MOSFET that comes in advanced DMOS, planer stripe technology.
• It is designed to achieve high switching performance. As it is an N-Channel MOSFET, so here conduction will be carried out by the movement of electrons.
• 5n50 usually consists of three terminals called source gate and drain. Conduction is achieved when electron emit from the source terminal and collected by the drain terminal.
• Conducting path between drain and source is called channel. Small positive voltage at the gate terminal is used to control the conduction between drain and source terminal.

• As we increase the initial input voltage at the gate terminal it will allow the conduction path between source and drain to increase, hence helps in increasing the overall conductivity of the channel.
• In this MOSFET, gate is practically isolated from drain and source and there lies an insulating layer between the gate and the body of the transistor. Sometimes it is referred as IGFET( Insulated Gate Field Effect Transistor), as gate is insulated and draws no current.

5n50 Pinout

This N-Channel MOSFET consists of three terminals which are given below. 1: Source 2: Gate 3: Drain  

• Voltage at the gate terminal is used to control the conduction between source and drain. And conduction is carried out by the movement of electrons.
• It comes in three different package named as TO-220, TO-252 and TO-262 receptively.
• All three types come with same characteristics but with different power dissipation values.

Working of 5n50

• As it is N-Channel MOSFET, so conduction will be done by the movement of electrons.
• In 5n50, the drain and source are composed of N type material while body and substrate is composed of P type material.
• The gate of this transistor is used composed of layer of poly-silicon.
• The addition of silicon dioxide on the layer of substrate gives the typical metal oxide semiconductor construction. MOS.
• The layer of silicon dioxide is a dielectric material so it will act as a capacitor where one of its electrodes will be replaced by the semiconductor.

• As we apply positive voltage at the MOS composition, it will alter the charge distribution in the semiconductor. With the addition of positive voltage, the holes present under the oxide layer will encounter a force and allow the holes to move downward. The depletion region will be accumulated by the bound negative charges which are connected with acceptors atoms.
• The accumulation of electrons at the p-type substrate increases the conductivity between the source and drain. At this point the electrical properties of p-type substrate will consistently inverts, allowing the substrate to change into n-type material.
• The addition of positive voltage at the gate terminal will control the movement of electron in the conducting channel between source and drain. The more we increase the voltage the more it will increase the overall width of conducting channel, hence ultimately increases the conductivity of transistor.
• Main advantage of this transistor over other bipolar junction transistor is that it needs no input current to handle the load current.

Maximum Ratings 5n50

Following figures shows the absolute maximum rating of 5n50.

• Drain-Source voltage is 500 V.
• Drain current is 5 A.
• Power dissipation is 38, 54, 125 W for different composition of MOSFET that comes  in three forms TO-220, TO-252, TO-262 repectively.

Applications

• 5n50 is an N-Channel MOSFET which is widely used in many electronic applications.
• It is used in active power factor correction.
• The ability of transistor to change its conductivity by the addition of positive voltage at the gate terminal is used for efficient amplification purpose.
• It is useful in many efficient power supplies where high switching is required.
• Some electronic lamps use this MOSFET for driving purpose.

That's all for today. If you have any query or question you can ask me in the comment section below. I'll try my best to help you in this regard. Thanks for reading the article. Stay Tuned for next article!

What is MOSFET? Definition, Full Form, Symbol & Working

Hey Guys! I hope everyone's fine. Today, we are going to have a look at What is MOSFET? We will cover MOSFET Definition, Full Form, Symbol, Working & Applications in detail.

MOSFETs are commonly used in many electronic applications. A number of MOSFETs are added in tiny memory chips or microprocessors that are widely used in cell phones and laptops. It is a voltage-controlled device that is used for amplification and switching purposes. I'll try to touch every area related to MOSFET. Let's get started.

What is MOSFET?

• MOSFET is an advanced type of FET, manufactured with controlled oxidation of semiconductor, having 4 Terminals, named:
  • Drain(D)
  • Gate(G)
  • Source(S)
  • Body(B)

where,

• Gate(G) Terminal is practically insulated from the entire assembly by a thin layer of Silicon-oxide(SiO2).
• Body(B) Terminal is connected internally with Source(S) Terminal & thus the MOSFET package consists of 3 pins.

• The below figure shows the MOSFET package, construction & symbol: (we will discuss them in detail below)

MOSFET Full Form

• MOSFET stands for "Metal-oxide Semiconductor Field Effect Transistor".

MOSFET Symbol

• Although MOSFET has 4 terminals, but as I have mentioned before, the 4th terminal is internally connected with the Source terminal & thus the package consists of 3 Pins, so as the MOSFET Symbol.
• MOSFET symbols are shown in the below figure:

Why MOSFET?

• Unlike BJT, MOSFET requires almost no input current & controls heavy current at the output.
• MOSFETs are quicker in operation than FETs, thus used in fast switching applications.
• FET has high drain resistance, while it's too low in MOSFET.

History of MOSFET

• MOSFET laid the foundation of modern electronics back in 1959 when it was invented at Bell lab by Mohammad Attala and Dawon kahng.
• MOSFET was presented to the world in the 1960s with a few tweaks in the original version of the device.
• In the 1960s the invention of MOSFETs led to rapid exponential growth of the semiconductor world, it enabled the use of semiconductors in integrated circuits and microcontroller units.
• MOSFET is compact and easy to use, which is why it is always in demand for mass production.

MOS Revolution

• The evolution and development of MOSFET led to a revolution in electronics which is labeled as the MOS revolution or MOSFET revolution.
• The birth of the Metal Oxide Semiconductor Field-effect transistor was regarded and cherished as the birth of modern electronics.
• MOSFET is one of the most widely mass-produced technologies of this era. Can you imagine the count of MOSFETs manufactured to date? By 2018 it was 13 Sextillion, unbelievable! Isn’t it?

MOSFET Construction

• Let's understand the construction of N-type MOSFET: In N-type MOSFET, two highly doped N regions are diffused into a single lightly-doped P substrate.
• Silicon Oxide(SiO2) layer is placed over Gate Terminal to create the insulation.
• Aluminum Probes are used for connecting terminals i.e. Gate, Drain & Source to respective regions.
• Silicon oxide(SiO2) layer is the main difference between FET & MOSFET and thus MOSFET is sometimes referred to as "FET with Insulated Gate" or "IGFET(Insulated Gate Field Effect Transistor)".
• Because of this oxide layer, MOSFET acts as a voltage controlled IC i.e. voltage at Gate Terminal decides the conductivity between drain and source.
• The conduction path between Source(S) and Drain(D) is called channel & its width is controlled by the Gate(G) voltage in MOSFET.
• MOSFET is a unipolar device i.e. conduction of current is carried out by the movement of either electrons or holes(majority charge carriers).
• N-Channel MOSFET internal Construction is shown in the below figure:

 

Types of MOSFET

MOSFETs are further divided into two types. MOSFET types are as follows:

1. N-Channel MOSFET.
2. P-Channel MOSFET.

Let's understand these MOSFET types, one by one:

N-Channel MOSFET

• In N-Channel MOSFET, a single P-layer is present between two N-layers & current flows because of negatively charged electrons(termed as majority charge carriers).
• Below figure shows the symbol, construction & block diagram of N-channel MOSFET:

P-Channel MOSFET

• In P-Channel MOSFET, single N-layer is present between two P-layers & current flows because of positively charged holes(termed as majority charge carriers).
• Below figure shows the symbol, construction & block diagram of P-channel MOSFET:

MOSFET Working Principle

In order to understand the working principle of MOSFET, we have to first understand its operational modes. Depending on the polarity of Gate Voltage, MOSFET operates in two modes, named:

1. Enhancement Mode.
2. Depletion Mode.

MOSFET Enhancement Mode & Depletion Mode

Let's take the example of an N-type MOSFET:

• If a positive voltage is applied at the Gate Terminal of N-type MOSFET, it starts conducting by creating a bridge between Drain & Source and termed as acting in Enhancement Mode.
• When a positive voltage is applied at the Gate terminal, the surface below the oxide layer starts attracting electronics while repelling holes.
• Hence, electrons get accumulated below the silicon oxide layer.
• As we increase the voltage at Gate Terminal, more electrons get attracted & thus conduction increases in N-Type MOSFET.
• If we reverse the voltage at Gate Terminal, N-type MOSFET will repel electrons and attract holes, thus the connection between Drain & Source will break & MOSFET is said to be in Depletion Mode.
• Both Operating Modes of N-Type MOSFET is shown in below figure:

MOSFET Characteristics

• In the composition of enhancement MOSFET, there must be minimum input gate-source voltage is applied to the gate before it starts conducting, this minimum voltage is called threshold voltage.
• In order to conduct these enhancement amplifiers, the gate-source voltage Vgs must be greater than the threshold voltage.
• Drain current Id will increase by increasing the forward biasing of MOSFET, making them suitable for efficient amplifier circuits.
• When we apply a fixed voltage between the drain and source Vds, we can plot the values of drain current Id for different values of the voltage across gate and source Vgs.

• These VI characteristics show the transconductance of the MOSFET. This transconductance is the ratio between the output drain current to the input gate-source voltage.
• For a fixed value of Vds, the slope of transconductance can be found as

gm= ?Id/?Vds

• This ratio is termed as transconductance which is a short form of "transfer conductance". The SI unit of transconductance is Siemens which is ampere per volt.
• The voltage gain of this MOSFET increases with the increase in transconductance and value of the drain resistor.
• At Vgs=0, N-Type enhancement MOSFET acts like an open switch or normally off, because field-effect won't be able to open the N-Type channel around the gate.
• Thus transistor will fall under the "cut-off" region at this point. The OFF condition of the MOSFET is represented by the dotted line, unlike the depletion region which shows a continuous line, showing the conduction region of the transistor.

• As we apply gate-source voltage Vgs at the gate terminal, it will start to conduct in the region between source and drain.
• The voltage at which transistors start conducting is known as threshold voltage and is represented by Vth.
• As we increase the gate-source voltage it will allow the conducting channel to go wider and ultimately increases drain current Id.
• It is important to note that the gate never conducts as it is practically isolated from the conducting channel between source and drain. MOSFET encompasses high impedance which is useful in many electrical amplifying circuits.
• If the threshold voltage is greater than gate-source voltage, then the channel will not conduct, it will only conduct when threshold voltage will be less than gate-source voltage Vgs.
• In the conduction or saturation region drain current can be calculated as
• Id= K(Vgs-Vth²)
• It is important to note that values of the threshold voltage Vth and K(conduction parameter) are different for different eMOSFET, these values don't vary physically as they come by default during the composition of the material from which transistors are made.
• It is clear from the figure above that graph on the right side starts as a parabola and then it becomes linear, and it gives the slope of the characteristic curve that increases with the increase in drain current for a fixed value of drain-source voltage Vds.
• In order to put the MOSFET in ON state, the gate of the transistor must be biased from its given threshold level.
• Biasing of gate terminal can be achieved using two different methods i.e. Zener diode biasing, and drain feedback biasing. Before biasing you must take one point into consideration that gate voltage must be greater than source by a value greater than the threshold voltage.

MOSFET as a switch

• It is the most basic and widely known application of the MOSFET.
• Consider the following circuit diagram, an N channel MOSFET is used in the enhanced mode to operate the lamp.
• When the positive voltage VGS is applied to the gate of the MOSFET, a channel is established and the lamp is turned ON.

• Similarly, when the gate voltage is zero the lamp turns off.
• MOSFET can only work as an analog switching circuit if it operates between the cut off region when the gate-source voltage is zero up to the saturated region where the VGS becomes saturated, you can go through the complete process by studying the characteristics curve of the MOSFET we have discussed in the earlier section.
• The circuit which we are discussing has a very small amount of resistive load, if you want to protect your MOSFET from overloading you need to connect it to a relay or a diode. If you are not providing enough protection to your MOSFET, you would eventually damage it.

Comparison of MOSFET with Other Transistors

MOSFET was practically designed to make amends in the performance of Junction Field-effect Transistors because they had very high drain resistance, a very slow processing speed, and they were a bit noisy as well. We have been discussing transistors lately and we are done with the detailed outlook of other transistors such as bipolar junction transistor and field-effect transistor as well, so let us compare all the three main types to summarize the concepts. It would help you revise the previously learned concepts as well.

MOSFET vs BJT

• The major difference between BJT and MOSFET is that BJT is a bipolar device in which conductivity is carried out by the movement of both electrons and holes while MOSFET is a uni-polar device in which conduction is carried out by the movement of electrons or holes.
• The three terminals in BJT called emitter base collector are analogous to MOSFET three terminals called source gate and drain respectively.
• Another area where MOSFET differs from BJT is that there is no direct connection between the gate and conducting channel of source and drain, unlike BJT where a small current at the base side is used to control the large current at the emitter and collector side. That's the reason MOSFET is also named IGFET (Insulated Gate Field Effect Transistor).
• BJT is a current-controlled device meanwhile MOSFET is a voltage-controlled device, for a better understanding you can read the article to know how a MOSFET is a voltage controlled device.
• MOSFET is preferably used in analog circuits and BLDC motors but bipolar junction transistors are not the first choice in this regard.
• We mainly use BJT for performing low current functions on the parallel lines MOSFET are implied in high power applications, don't worry we will discuss the appliances of MOSFET in later sections.

MOSFET vs JFET

Both MOSFET and JFET belong to the same family of field-effect transistors.

• MOSFET has four components meanwhile the JFET has three components, three components namely the base source and drain are the same meanwhile the only different component is the Body of the MOSFET.
• MOSFET has a higher input impedance than the JFET.
• MOSFET has higher drain resistance than JFET because of the already established conduction channel of MOSFET.
• MOSFET make less noise than the JFET
• JFET is less costly and easy to manufacture because of the absence of a metal oxide layer that is present in MOSFET.
• MOSFET can easily be damaged due to low input capacitance meanwhile a higher input capacitance saves the JFET from immediate damage.
• JFET has a higher gate current than the MOSFET.
• MOSFET can work in two modes, depletion-mode as well as enhancement mode, on the other hand, JFET only works in depletion mode.

MOSFET vs IGBT

• IGBT is the insulated Gate Bipolar Transistor meanwhile MOSFET is the metal oxide semiconductor field-effect transistor
• IGBT is the combination of the bipolar junction transistor with the MOSFET, meanwhile, the MOSFET is the true transistor.
• MOSFET are not tolerant to electrostatic discharges meanwhile an IGBT is highly stable in this regard.
• The IGBT is tolerant of overloading meanwhile a MOSFET is susceptible to damage because of overloading.
• IGBT is used in high power applications, on the parallel lines, the MOSFET has a relatively lower capacity to deal with such high power applications like IGBT.

MOSFET Review

• MOSFET is a type of FET that is a unipolar device i.e. single charge carriers are responsible for the conduction between source and drain.
• The voltage applied at the gate side is used to control the current flowing through conducting channel between source and drain.
• MOSFET is a voltage-controlled device, unlike BJT which is a current-controlled device.
• Practically, the gate of the MOSFET draws no current. However, a small amount of initial current is needed to charge the capacitance of the gate terminal.

MOSFET Applications

• MOSFET is mostly used as an electronic automatic switch in both analog & digital circuits.
• It is widely used in applications where high amplification is required.

That's all for today. Hope you have got a clear idea about MOSFET. If you have any questions you can ask me in the comment section below. I'll try my best to resolve your query as soon as possible. Your feedback and suggestion will be highly appreciated. It will allow us to give you quality work based on your needs and expectations. Stay tuned!  

Introduction to 1n4733a

Hey Fellas! I hope you are enjoying your life with love, care and passion. Today I'm going to give you the details on the Introduction to 1n4733a. It is a Zener Diode which works similar to normal diode with only exception, it can also conduct in reverse biased condition. Zener diodes are considered as a basic building components for many electronic circuits. I will try my best to give you the details on almost every feature of this zener diode so you don't need to go anywhere for finding the information regarding this zener diode. Let's get started.

Introduction to 1n4733a

• 1n4733a is a normal p-n junction diode which allows the current to flow in both directions i.e. forward direction and reverse direction.
• In other words, it conducts in both ways i.e. when it is forward biased, also when it is reverse biased.
• In order to conduct in reverse biased condition, reverse breakdown voltage must be achieved.
• Over a wide range of voltages, voltage drop across the zener diode doesn't change which makes it ideal for using for voltage regulation purpose.
• Unlike normal diodes, zener diodes work in breakdown region and are best for generating reference voltage.

• This zener diode comes with a highly doped p-n junction and sealed glass package that gives solid protection in all common atmospheric conditions.
• It is widely used to prevent the electronic circuits from over voltage.
• 1n4733a comes with different voltage rating ranging from 3.3 V to 91 V.
• It offers double slug construction which is corrosion resistant. And the leads that come with this zener diode are easily solderable and can withstand the maximum temperature up to 230 C.
• It encompasses excellent working characteristics and have power of 1 W.  The voltage tolerance appears to be 5%.

Working of 1n4733a

• Working principle of this zener diode is similar to common diode with slight difference.
• Zener diode In4733a acts like a normal diode in forward biased condition.
• It exhibits a turn on voltage that ranges between 0.3 to 0.7 V.
• It only conducts in the reverse direction when reverse voltage reaches to the breakdown voltage, allowing the current to flow from cathode to anode.
• Current reaches to maximum and stabilizes itself after a certain amount of time over a wide range of applied voltage which makes it suitable for using as a voltage stabilizer.
• Voltage breakdown occurs due to the Zener breakdown effect. It may also occur due to impact ionization. Both mechanism occur at 5.5 V., encompass same feature and don't need different circuitry in order to work perfectly. However, temperature coefficient of both mechanisms is different. Zener effect shows negative temperature coefficient and impact ionization shows postitive temperature coefficient. Both effects cancel each other at 5.5 V, making the zener diode achieve the most stable state over a wide range of temperatures.

Zener 1n4733a used for different Purposes

Zener diodes have a wide range of application specially when it comes to voltage regulation. This zener diode comes with many specifications and applied to electrical circuits in different forms as follow.

As a Voltage Regulator

• Zener diodes are useful to regulate the voltage in many small circuits. When zener diode is connected in parallel with the voltage in reverse biased mode, it will start conduction when voltage equals to a breakdown voltage.

• In the above figure, source voltage is applied in parallel with the diode. It will perfectly decrease the output voltage from its input, while keeping the breakdown voltage constant over a wide range of source voltage. Output voltage will remain stable, even the fluctuation in source input voltage won't effect the output voltage due to constant breakdown voltage.

Waveform Clipper

• Zener diodes are also used as a wavefrom clipper when they are connected in series. Following is the figure of two zener diodes connected in series.

• When zener are connected in series, it allows the waveform to clip from both ends of the cycle i.e. positive end of the cycle and also negative end of the cycle.
• Zener diodes connected in series also prevent the high voltage spikes at the end of the output signal, allowing the reshaping of output voltage.

Voltage Shifter

• Zener diode can also use for shifting the output voltage.
• When it applies as a voltage shifter, it drops down the output voltage by the quantity equal to breakdown voltage.

That's all for today. I hope you have now got a clear idea about working principle of 1n4733a and how it is used for different purposes. However, if you have any confusion, you can ping me a message in the comment section below, I'll be glad to help you in this regard. Your feedback and suggestions will be highly appreciated. Brace yourself for next article. Stay Blessed!

Introduction to JFET

Hello Guys! I hope you are doing great and having fun. I am back to give you a daily dose of knowledge that will enhance your learning skills and put you ahead of others. Today, I am going to give you details on the Introduction to JFET. It is a Junction Field Effect Transistor that consists of three terminals named drain, source and gate. It comes in two configurations called the P-Type channel and the N-Type channel. I'll give you brief details on JFET and try to cover as many aspects as possible. Let's get started:

Introduction to JFET

• JFET (Junction Field Effect Transistor) is a uni-polar voltage-controlled device that consists of three terminals called drain, source and gate.
• Unlike bipolar junction transistors which are bipolar current-controlled devices in which a small amount of base current is used to control a large amount of current at the collector and emitter side, JFET is a uni-polar voltage-controlled device in which voltage applied to the gate terminal allows the current to flow through JFET, resulting in input applied voltage equals to the current flowing through the transistor.

• In JFET, gate is always negatively biased as compared to source.
• As compared to bipolar junction transistors, JFET are uni-polar because current carriers in case of JFET are either electrons or holes while bipolar junction transistors are operated by the movement of both electrons and holes.
• The operation of JFET depends on the electric field created by input applied voltage, hence it is called Field Effect Transistor.

• JFET can be classified into two types on the bases of their operation i.e. N-Type and P-Type JFET.
• In JFET, current carrying path between drain and source is called channel which contains no pn-junction. Channel can be made up of P-Type or N-Type semiconductor.
• Current flowing through this channel widely depends on the input voltage applied to the gate terminal of JFET.
• Field effect transistors generally comes in two types JFET (Junction Field Effect Transistors) and MOSFET( Metal Oxide Semiconductor Field Effect Transistors)
• As stated earlier, JFET contains no pn-junction, instead it comes with channel that consists of N type or P type semiconductor that passes between source and drain terminals of JFET.

JFETs are classified into two main configurations.

1. N-Type Configuration
2. P-Type Configuration

1: N-Type Configuration

• In N-Type configuration current flowing through the channel is negative i.e. current flow is carried out by the flow of electrons which are also termed as donor impurities.

• The measure of conductivity of electron in N-Type configuration is much higher than the holes in P-Type configuration, because electrons come with high level of mobility than holes. Hence, in terms of conductivity, N-Type configuration is more efficient than P-Type configuration.
• Channel is a conducting path between drain and source. Within this channel, there lies a third terminal called Gate at which input voltage is applied that is used to control the current flowing through the JFET.
• As channel is resistive in nature, resulting in creating the voltage gradient which becomes less positive as we move from drain to source terminal. This less positive voltage makes drain terminal high reverse biased and source terminal low reverse biased. This bias creates a depletion region whose width is directly proportional to the bias itself.
• The current carrying path between source and drain is controlled by the voltage applied to the gate terminal. In an N-Type configuration of JFET this gate voltage is negative while in case of P-Type configuration it is positive.
• It is important to note that gate current in reverse biased condition in the JEFT is practically zero, while base current in Bipolar junction transistor always comes with a value greater than zero.

N-Type Channel Biasing

• Following is the figure shows N-Type semiconductor with P-Type material which forms the reverse biased PN-junction that creates a depletion region around the gate terminal of JFET.

• Depletion region will be created in the absence of external voltages. JFET are also termed as depletion mode components.
• The depletion region will create a voltage gradient of some thickness which ultimately limits the flow of current, hence results in increasing the overall resistance of FET.
• It is clear from the figure above that most part of depletion region lies between the gate and drain terminals which least part lies between the gate and source terminals which means resistance between gate and drain terminal appears more than the resistance between gate and source terminals.
• In the absence of external input voltage at gate and small voltage at the drain and source Vds allows the saturation current to flow between drain and source.
• The amount of current flowing through the pn-junction will be restricted by the depletion region around the pn-junction.
• It is important to note, if we apply negative voltage at the gate and source Vgs terminals, it will cause the depletion region to grow which ultimately restricts the flow of current, hence results in decreasing the overall conduction of transistor.
• If the voltage applied at the gate terminal Vgs appears to be more negative, it will allow the depletion region to increase and results in decreasing the overall width of channel. The moment comes when applied voltage at gate terminal appears to be negative to the point that will squeeze the channel and won't allow a fraction of current to flow between source and drain terminals.
• The negative voltage applied to the gate terminal at which no current flows between drain and source terminals is called "Pinch-off Voltage".
• In pinch off region negative voltage at the gate terminal Vgs controls the overall conductivity of the channel. This is the reason JFET are called voltage controlled devices.
• Voltage appears at the gate terminal must not be positive, otherwise it will make resistance zero and allows the current to flow between gate terminal instead of source terminal. Positive voltage at the base terminal can damage the transistor at large.

2: P-Type Configuration:

• In P-Type configuration current flowing through the channel is positive i.e. current flow is carried out by the flow of holes which are also termed as acceptor impurities. Both N-Type and P-Type configurations come with same characteristics with some exceptions.

1. Current carriers in N-Type configuration are electorn, hence current appears to be negative
2. Current carriers in P-Type configuration are holes, hence current appears to be positive.
3. Biasing voltage in P-Type configuration comes with reverse polarity.

• The voltage applied at the gate terminal is used to control the current flowing between source and drain. As JFET is a voltage controlled device and no current flows through gate terminals Ig=0. Hence in that case, current flowing out from source terminal will be equal to the current flowing into the drain terminal i.e. Is=Id

 

V * I Curves of N-Channel JFET

Following figure depicts the four region of operation of JFET.  

• Ohmic Region: Region is called ohmic region when Vgs=0. In this region JFET operates like a voltage controlled resistor.
• Pinch off  or Cut-off Region: It is region at which voltage applied to the gate is negative to the point which causes depletion region to increase and allows the current carrying width to decrease till it disappears, resulting in maximum resistance to appear and current flowing through the channel will be zero.
• Active or Saturation Region: The region that is controlled by gate voltage Vgs and where JFET becomes good conductor is called active region. Vds has no effect on active region.
• Breakdown Region: Region is termed as breakdown region where voltage between source and drain appears to be maximum to the point where it breaks the resistive channel and allows the current to flow between the channel.

V * I Curves for P-Type JFET

• The curves for P-Type configuration appear to be same with one exception i.e. Increase in positive voltage at the gate terminal will decrease the current at the Drain terminal Id.

Formula for Drain Current and Drain-Source Channel Resistance

• Drain current at the saturation region can be calculated as follows:

Id= Idss * [ 1 - Vgs / Vp ]

• Id lies between zero to Idss.
• Similarly, if we know drain source voltage Vds and drain current Id, we can calculate the drain-source channel resistance.

Rds = ?Vds / ? I d = 1 / gm

• Here gm represents the "transconductance gain"

Different Modes of Operation of FETs:

FETs can be classified into three different modes of configuration.

1. Common Source Configuration
2. Common Gate Configuration
3. Common Drain Configuration

1: Common Source Configuration CS:

Common source configuration is an analogous to the common emitter configuration in the bipolar junction transistors. In this configuration input voltage is applied to the gate terminal and output we get is from the drain terminal. This mode of operation comes with amplified voltage and high impedance, hence it is mostly used in high audio frequency amplifies. As this is an amplifying circuit, it allows the output to be diverted 180º from its input.

2: Common Gate Configuration CG:

Common gate configuration is an analogous to the common base configuration in the bipolar junction transistors. In this configuration input voltage is applied to the source terminal and output appears at the drain terminal while gate is connected to ground. In this configuration impedance will be low as compared to common source configuration. This configuration is mostly used in high frequency and impedance matching circuits. Unlike common source configuration, here "output signal is in phase with the input signal"

3: Common Drain Configuration CD:

Common drain configuration is an analogous to the common collector configuration in the bipolar junction transistors. In this configuration input voltage is applied to the gate and output signal is collected from the source. It is important to note there is no signal applied to the drain terminal. Vdd simply depicts the bias voltage. Similar to common gate configuration, here "output signal is in phase with the input signal"

Comparison between BJT and JFET

• • Both, bipolar junction transistors and uni-polar field effect transistors encompass same characteristics with some exceptions.
  • BJT are bipolar devices i.e. they are operated by the movement of both electrons and holes. JFET are unipolar devices i.e. they are operated by the movement of either electrons or holes.

• As compared to Bipolar junction transistors, JFET comes in much smaller form and can be used in many tiny electronic chips.
• One major feature that differentiates between bipolar junction transistors and JFET is the input impedence. It is very high in case of JFET while it appears very low in bipolar junction transistors.

Applications

• JFET are widely used in many electronic appliations. They are mainly used for amplification purpose.
• JFET are used to obtain high frequency audio signal.
• They are useful for obtaining impedance matching circuits.

That's all for today. I hope you have got a clear idea about JFET. However, if still you feel any doubt or query in understanding the concept of JFET, you can ask me in the comment section below. I'll be glad to help you in this regard. Your feedback and suggestion will be highly appreciated. It will help us give you quality work that resonates with your needs and expectations. Stay tuned!

Introduction to BF259

Hello Friends! I am back again to fill your appetite with more knowledge and skills. Today, I am going to explain the details on the Introduction to BF259. It is a bipolar NPN (negative-positive-negative) silicon transistors which comes in metal casing. It consists of one P layer that lies between the two layers of N doped semiconductor. I am going to cover all aspects related to this bipolar transistor. Let's get started and have a look, how it works and what are the applications it finds useful.

Introduction to BF259

• BF259 is a bipolar silicon transistor which is made up of two N doped layer and one P doped layer.
• It is mainly a three terminal device which consists of emitter base and collector.
• P terminal of the transistor acts like a base while other two sides of P layers act as emitter and collector respectively.
• Small current at the base is used to control a large amount of current at the collector and emitter side.
• The power it can dissipate is 1 W, while transition frequency is about 75 MHZ.
• DC collector current is 100mA.
• Maximum power dissipation across collector is 0.5 W.
• BF259 is also considered as a current operated device.

• Maximum collector base voltage is 300 V and is denoted by Vcb.
• Maximum collector emitter voltage is 300 V and is denoted by Vce.
• It comes with lots of major applications but mainly it is used for switching and amplification purpose.

1. BF259 Pinout

BF259 NPN silicon transistor consists of three terminals. 1: Emitter 2: Base 3: Collector Actual pinout of this NPN transistor is given in the figure below

• The base current is used to control the large amount of current on the collector and emitter side.
• The way the base current impact the emitter and collector current is used for the amplification applications.
• This bipolar transistor will turn ON when current flows from emitter and collector.

2. Mechanical Outline of BF259

The mechanical outline of bipolar silicon transistor BF259 is shown in the figure below:

• All the dimension are given in mm.
• You must take these dimension into consideration before you plan to make a circuit so these dimension properly fit in the circuit.

3. Circuit Diagram of BF259

The circuit symbol of BF259 is shown in the figure below:

• This NPN silicon transistor comes with a positive base side and negative emitter side.
• Emitter current is the sum of base and collector current.
• Small amount of current at the base side is used to handle the large amount of current at the emitter and collector side.
• Main difference between NPN and PNP transistor is, Current will sink into the base side in case of PNP transistor while current from the base side will source to the transistor in case of NPN transistor.
• Transistor current can be found by dividing the collector current to the base current. It is also called beta current and is denoted by ß. Beta has no units as it is a ratio between two currents.
• Value of beta is used for the amplification purpose. Beta value ranges between 20 to 1000, however, its standard value is 200.
• The ratio between collector current to the emitter current is called current gain of the transistor and is denoted by alpha a.
• The value of alpha ranges between 0.95 to 0.99, however, in most of the cases it is considered as 1.

4. Absolute Maximum Rating BF259

The maximum absolute rating of BF259 is shown in the figure below.

• Units of current and voltage are mA and V receptively.
• These rating are important for many engineering projects.

5. Applications

• BF259 is also called high voltage video amplifier and is mostly used for high voltage video output.
• It is also used for the audio output stages.
• These transistors are the main drivers for horizontal deflection circuits.

That's all for today. If you have any question you can easily ask in the comment section below. I'll try my best to help you solve your queries. Your suggestion and feedback will be highly appreciated. Stay tuned for next article.

Introduction to 2n4402

Hey guys! I aspire you a prosperous life filled with joy and happiness. Today, I am going to uncover the details on the Introduction to 2n4402. It is basically a PNP (Positive-Negative-Positive) silicon transistor where N doped layer lies between the two P doped layer. It consists of three terminals i.e. emitter, base, collector. Here N represents the base of the transistor and two P layers represents the emitter and collector respectively. I'm going to cover all aspects related to this transistor. Let's hop on the board and dive in the details of this silicon transistor.

Introduction to 2n4402

• 2n4402 is a bipolar silicon transistor, where one layer of N doped semiconductor is sand-witched between the two layers of P doped semiconductor.
• It works in a way, the small current at the end of the base is used to control a large amount of current at the end of collector and emitter.

• PNP transistor works in a similar way to NPN transistor with the exception of current carriers. In case of NPN transistors, current carriers are electron while current carriers in the case of PNP transistors are holes and direction of current and polarities of voltage will be reversed in this case.
• In PNP transistor, P letter represents the polarity of voltage applied to the emitter which is positive and N letter shows the polarity of voltage applied to the base which is negative. In order to conduct in PNP transistor, Emitter will always be more positive than base and collector.

2n4402 Pinout

2n4402 consists of three pins

• 1: Emitter
• 2: Base
• 3: Collector

 

• Unlike NPN transistors, here current flows from emitter to collector and current carriers are holes.

PNP Circuit Symbol

• Following is the circuit symbol of PNP transistor. It consists of two P layers and one N layer.

 

• The polarity at the emitter side is positive with respect to both base and collector.
• The base of this transistor is negative with respect to emitter.
• Current flowing through the emitter side is the sum of current flowing through collector and base.
• Small amount of current at the base side is used to control the large amount of current at the collector and emitter side.
• PNP and NPN works in similar way with the exception of current direction and medium used for the flow of current.
• In PNP transistor current flows from emitter to collector and current carriers in this case are holes which are collected by the collector.

PNP Transistor Configuration

• Transistor configuration of PNP 2n4402 transistor is shown in the figure below:

• Emitter is positive with respect to collector and base
• Small amount of base current is used to control the large current at the collector and emitter side.
• Current carriers are holes which are collected by the collector.

Transistors as a Matched Switch

• In most of the cases, PNP transistors replace the NPN transistor with the only exception in the direction of current and polarities of voltages.
• Like NPN transistor, PNP transistor can also be used as a switching device.
• You might think what is the point of using PNP transistor while there are lots of NPN transistors out there that can be used as a switch or for amplification purpose. However, taking two types of transistors come with a lot of advantage in designing the power amplifier circuit.
• Class B-amplifiers come with a two pair of NPN and PNP transistor, where both transistors are used to control the current flowing in both directions at any instant of time. Transistors are called "Complementary Transistors" which use both NPN and PNP transistor of identical characteristics.
• In Class B-amplifiers, both transistors work in a similar way i.e. NPN transistors conducts for the positive half cycle and PNP transistor conducts for the negative half cycle of the transistor. This results in flowing the power at the load out put in both directions. PNP transistors will switch on when it sinks current to its base side and it will switch off when current at the base side stops to flow.

Applications of 2n4402

• These transistors are mainly used for voltage and power amplification.
• In combination with NPN transisters, these PNP transistors form a perfect bond through which current flows alternately from both sides of NPN and PNP transistors.

That's all for today. I hope you'd enjoyed our article. If you have any query or question you can easily ask in the comment section below. I'd be glad to help you in this regard. Your suggestion and feedback will be highly appreciated. Stay tuned for next article.

Introduction to Resistors

Hey guys! I hope you are doing good and having fun. Today, I am going to unlock the details on the Introduction to Resistors. Resistor is a two terminal component that is used to restrict the flow of current. Resistors are widely used in electrical circuits. They come in different forms ranging from variable resistors to fixed resistors. Depending on the feature of resistors, both are used in many applications. I am going to cover all aspects relating to resistors. Let's get started.

Introduction to Resistors

• A resistor is a two-terminal device that is used to resist the flow of current. It is one of the most commonly used components in electrical circuits.
• Resistance of any resister is described in ohms. Ohm is denoted by the Greek letter omega. Each resister has a different value of resistance which tells us how strongly it resists the flow of current. More the value of resistance more is the capability of resisting the current.
• Resistance will be considered as one ohm if the potential difference between the two ends of the conductor is 1 V and a current flowing through it is 1 Ampere.
• Resistance can be derived from Ohm's law which indicates voltage is directly proportional to the current flowing through the conductor.

V= I * R

• Each resistor comes with two wires, also called as leads. Between these two leads there lies a ceramic part which actually resists the flow of current. Resistor consists of three colored strips that indicate the value of resistance.
• Some resistors come with four colored strips. In such case, fourth strip indicates the value of tolerance. Tolerance is the value of the deviation of resistance from its given value on the resistor. Gold color of forth strip indicates tolerance is 5% and silver color indicates tolerance is 10%. Where there is no forth strip, tolerance is considered as 20%. Suppose, if resistance has 50-ohm resistance with no forth strip. Then tolerance of such resistor can be 50 ±20%.
• Resistance of any resistor also depends on its resistivity, its length and cross-sectional area.

• Resistors also indicate temperature coefficient. Temperature coefficient is known as a resistance due to the change in temperature. There are two types of temperature coefficients. Positive temperature coefficient and negative temperature coefficient. If resistance increases with the increase in temperature then it is called positive temperature coefficient and if resistance decreases with the decrease in temperature then it is called negative temperature coefficient.

How to Limit Current using Resistance

• Main purpose of resistance is to limit the current flowing through the component.
• Suppose, if we want to connect the LED with the direct DC source i.e. Battery, then it will burn out right away the moment you connect the LED with the battery.
• Because battery will allow a large amount of current to flow through the LED which will burn it out.
• LED can be avoided from any severe damage if we put the resistor between the battery and LED. It will control the amount of current flowing through the LED.
• Value of resistance you use depends on the current rating of the battery. You need to use the resistor with high resistance if current rating of a battery is high.
• We can calculate the resistance by using Ohm's Law. Suppose we have LED that comes with voltage rating of 12 voltage and current rating of 100mA or 0.1 A. From Ohm's Law

V=IR

R= V/I

R=12/0.1= 120 O

• In order to avoid LED from damaging we need resistor with resistance of 120 O

 

Combination of Resistors

Resistors can also be used in combination. There are classified into two types according to their combination.

Resistors in Parallel

• If resistors are connected parallel to each other, then total resistance will be equal to the sum of reciprocal of all resistance.

1/R= 1/R1+1/R2+1/R3............1/Rn

Resistors in Series

• If resistors are connected in series, the total resistance will be equal to the sum of all resistance.

R= R1+R2+R3+R4..........Rn

Power Dissipation

• The power consumed by any resistor at any moment is defined as
• P= VI= V(V/R)= V²/R
• Most of the resistors are classified on their ability of power dissipation. Resistors who dissipate a large amount of energy are called as power resistors and are mostly used in power supplies, power amplifiers, and power conversion circuits.
• Power resistors are physically larger than normal resistors and their value cannot be directly identified by the reading color strip method.
• Resistors pertain to severe damage if their average power dissipation is greater than thier power rating. It results in permanently alternating the resistance.
• Excessive power dissipation can also damage the whole circuit. In order to avoid burning of the circuit, flameproof resistors are used that suddenly open the circuit before power dissipation gets too high.

How to Calculate Resistance of any Resistor

There are two different ways to calculate the resistance:

Reading the Color Bands

• First method to calculate the resistance is by reading the color bands of the resistor.
• Each strip of color on the resistor represents a specific digit.
• Different colors corresponding to their digit values are given below.

• In the above figure, the first strip is brown and corresponding digit to brown is 1.
• The second strip is black, and the corresponding digit to black is 0.
• The third strip is orange and the corresponding digit to orange is three which actually shows the number of zeros.
• Forth strip is made of gold which indicates tolerance is ±5%.
• So overall resistance of this resistor is 10,000±5 % ohm.

Using a Multimeter

• Second method to measure the resistance is by using the multimeter as an ohmmeter. Mainly multimeter performs three functions. It is used to measure current voltage and resistance.
• Put the black probe on the COM port of multimeter. And put the red probe into the VOmA.
• You can measure the resistance of any resistor by holding the resistor with the two separate probes of the multimeter. Before calculating the resistance, you need to set the dial to ohm which is denoted on the multimeter by the symbol O.

 

Types of Resistors

Resistors come in different forms, sizes, and shapes. Resistors are used in different applications depending on the current rating voltage and resistance. Let's discuss resistor types and their applications. Resistors are mainly classified into two types:

1. Linear Resistors
2. Non-Linear Resistors

1. Linear Resistors

• Resistors are termed as linear resistors where current is directly proportional to the applied voltage.
• Resistance of these resistors changes with the change in temperature and voltage.
• In order words, resistors which follow Ohm's law are linear resistors.
• Linear resistors are further classified into two types
  • Fixed Resistors
  • Variable Resistors

1.1 Fixed Resistors 1.1.1 Carbon Composition Resistor

• Carbon composition resistors comprise of rigid resisting element incorporated with lead wire. The resistor body is covered with plastic or paint.
• The resistive element at the mid of the lead wires contains fine carbon and insulating material which is usually ceramic. The resistance of such resistors is measured as the ratio of ceramic to carbon.
• Resistance value widely depends on the concentration of carbon value. More is the concentration of carbon, lesser will be the resistance.
• Carbon composition resisters come with poor stability and 5% tolerance.
• These resistors are become obsolete because of their high price but still they are used in wielding controls and power supplies.
• Resistance of such resistors varies from few ohms to 22 mega-ohms.

1.1.2 Carbon Pile Resistor

• A carbon pile resistor consists of layers of carbon discs that are placed between two metal plates.
• Resistance between the plates can be changed by changing the clamping pressure.
• These resistors are widely used in radio transmitters.
• A carbon pile resistor can also be used in generators, where it adjusts the current to keep the voltage in certain state.

1.1.3 Carbon Film Resistor

• A carbon film resistor consists of amorphous carbon which provides relatively large resistance.
• These resistors encompass low noise as compared to carbon composition resistor.
• A carbon film resistor comes with a power rating that ranges between 0.125 to 5 W with resistance 1 ohm to 10 mega-ohm. These resistors are used in areas where high stability is required.

1.1.4 Thick Film Resistor

• Thick film resistors come in the shape of SMD(Surface mount device).
• Both, think and thin film resistors are manufactured in a same way but main difference is the resistive element that is used in thick film resisters is relatively very large than used in thin films.

1.1.5 Thin Film Resistor

• Thin film resistor consists of ceramic rod and resistive material.
• A very thin layer of conducting material is being placed on the insulating rod that is made of glass or ceramic material. This method of making thin film is called vacuum deposition.
• When thin film resistor is manufactured, it doesn't give an accurate value of resistance.
• Resistance value can be made accurate by the process called laser trimming.
• These resistors come in the tolerance range that lies between 1% to 5% and encompass much less noise level than thick film resistors.
• Compared to thick film resistors, thin film resistors are highly expensive.

1.1.6 Wire Wound Resistors

• Wire wound resistors are widely used in many electrical applications. They are manufactured by winding a metal wire around fibreglass core or ceramic material. Whole assembly is being formed where two ends of wire are welded with rings and are covered with high layer of molded plastic or paint.
• These resistors have capability to bear high temperature upto 450 ºC.
• As wire wound resistors are same like coil so they inherit high value of inductance as compared to other resistors.
• Both, carbon composition resistors and wire wound resistors are used in same application except where high frequency is required. High frequency response of carbon composition resistors is better than wire wound resistors.

1.2 Variable Resistors

• Resistors are termed as variable resistors whose values can be adjusted manually by screw, knob, or dial.
• These resistors come with sliding arm that is attached to the shaft.
• Resistance value can be changed by rotating the sliding arm.
• They are mainly divided into two types:
  • Rheostats
  • Potentiometer

1.2.1 Rheostats

• Rheostat resistors are also known as variable wound resistors or tapped resistors.
• Rheostat is a manual operated three terminal device which is mainly used to restrict the current value.
• In order to make rheostat, Nichrome resistance is being wound around a ceramic core, then they are placed in a covered shell.

  1.2.2 Potentiometer

• A potentiometer is a three terminal device that consists of tapping points that are adjusted by a rotation of shaft.
• It can be used to provide a potential difference between the two terminal connected to the tapping points.
• They are widely used for volume control in many radio receivers.
• Potentially there is no difference between rheostat and potentiometer, however, both are used for difference purpose.
• Rheostat is used for controlling the level of current in the circuit while potentiometer is used for controlling the voltage in the circuit.

 

2. Non-Linear Resistors

• Resistors are termed as non-linear resistors where they do not pertain to follow ohm's law but their value of resistances changes with the slight change in temperature or current.
• Non-linear resistors are further divided into two types:
  • Thermisters
  • Varisters

2.1 Thermisters

• Resisters are termed as thermisters, if current flowing through it changes with the change in temperature.
• Thermister is basically a two terminal device which uses variable resister and indicates even a slight change in temperature.
• In thermister, resistance and temperature are inversely proportional to each other.

2.2 Varisters

• Resisters are termed as varisters if current flowing through it changes with the change in applied voltage.
• These resistors are sensitive to voltage and avoid the circuits from getting high voltage spikes.
• They are used to maintain the voltage to a required level.

Applications of Resistors

Resisters are widely used in many electrical circuits. Following are the main applications of resistors.

• They are used to limit current in order to avoid short circuit
• They are used to control voltage in order to avoid high spikes at the end of out put voltage
• Used in many electronic industries
• Temperature can also be controlled using these resistors
• In home electronic appliances like heater and iron

That's all for today. I have tried my best to cover as many aspects as possible relating to resistors. However, if still you feel any doubt or query in understanding the concept of resistors, you can always ask me in the comment section below. I'll be glad to help you in this regard. Thanks for reading the article. Give your feedback, how do you like our articles what are the suggestions you would like to give that can help in crafting the articles in better way? Stay tuned for next article! Have a blessed day ahead!