This article is all about the Basic Fundamentals of Engineering. In this, I am going to explain the basic components and their applications which come across while making projects of engineering, why we use these components, and what actually they are. This article is going to be very helpful for the beginners or the one who has just stepped in this field.
- 1 Introduction
- 2 1) What is the Diode?
- 3 The symbol used for diode
- 4 Types of diode
- 5 Descriptions of all types of diodes mentioned above:-
- 6 2) What is a transistor?
- 7 Symbol used for Transistors
- 8 Types of Transistors
- 9 Bipolar Junction Transistor(BJT)
- 10 The Field-Effect-Transistor (FET)
- 11 NPN Transistor
- 12 PNP Transistor
- 13 Junction Field Effect Transistor(JFET)
- 14 Heterojunction Bipolar Transistor(HBT)
- 15 Darlington Transistor
- 16 Metal–oxide–semiconductor field-effect transistor(MOSFET)
- 17 3)What is a Capacitor?
- 18 Symbol used for Capacitors
- 19 Types of Capacitor
- 20 Ceramic capacitor
- 21 Electrolytic capacitor
- 22 Tantalum capacitor
- 23 Silver Mica Capacitor
- 24 Polystyrene Film Capacitor
- 25 Polyester Film Capacitor
- 26 Polycarbonate capacitor
- 27 Polypropylene Capacitor
- 28 Glass Dielectric capacitors
- 29 4)What is Resistor?
- 30 Linear Resistor
- 31 Fixed Resistor
- 32 1) Carbon Composition Resistors
- 33 2) Wire-wound Resistors
- 34 3) Thin Film Resistors
- 35 3.1.Carbon Film Resistors
- 36 3.2. Metal Film Resistors
- 37 4) Thick Film Resistors
- 38 4.1) Metal Oxide Resistors
- 39 4.2) Cermet Oxide Resistors
- 40 4.3) Fusible Resistors
- 41 Variable Resistors
- 42 1) Potentiometers
- 43 Symbols used for Potentiometer
- 44 2) Rheostats
- 45 The symbol used for Rheostat
- 46 3. Trimmers
- 47 The symbol used for Trimmer
- 48 2. Non-Linear Resistors
- 49 2.1) Thermisters
- 50 The symbol used for thermistor
- 51 2.2) Varistors (VDR)
- 52 The symbol used for Varistor
- 53 2.3) Photo Resistor or Photo Conductive Cell or LDR (Light Dependent Resistors)
- 54 Symbol used for LDR
- 55 Applications of Resistor
- 56 Resistor color code
- 57 Example:
- 58 5) what is the printed circuit board(PCB)?
- 59 6) what is breadboard?
1) What is the Diode?
It is an electronic component and it permits the current to flow in one direction(forward direction).It is usually used in electronic circuits and used to convert alternating current (AC) into direct current (DC).Diodes is a semiconductor device having two terminals or electrodes positive and negative (anode & cathode).Most diodes are manufactured with semiconductor materials silicon, germanium, or selenium.
The symbol used for diode
Types of diode
Descriptions of all types of diodes mentioned above:-
Signal Diode: It is a non-linear semiconductor device mostly used in electronic circuits. Signal Diodes are manufactured in a range of voltage and current ratings and care must be taken when choosing a diode for a certain application. There is a bewildering array of static characteristics associated with the humble signal diode but the more important ones are. signal diodes are also found as a switch in rectifiers, snubbers, limiters, and wave-shaping circuits.
A light-emitting diode (LEDs): It is an electronic device that glows up when current is passed through it. A light-emitting diode (LED) is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a device is known as an infrared-emitting diode (IRED). Their colors- red, green, blue & yellow colors.
Infrared LEDs (IR LEDs): It is an electronic component that sends out light with longer wavelengths. An IR LED (infrared light-emitting diode) is a solid-state lighting (SSL) device that emits light in the infrared range of the electromagnetic radiation spectrum.IR LEDs allow for cheap, efficient production of infrared light, which is electromagnetic radiation in the 700 nm to 1mm range.
Photodiode: it is a semiconductor device which converts light into an electric current. It is operated in reverse bias conditions.It is also sometimes referred as photo-detector, photo-sensor, or light detector.
The different types of photodiodes are-
- PN junction photodiode
- PIN photodiode
- Avalanche photodiode
Transient Voltage Suppression Diodes: It is an electronic component used to protect electronic devices from voltage fluctuation. TVS diodes are also used to protect circuits from electrostatic discharge. Silicon-avalanche diodes (SAD) and Zener diodes are the common types of circuit protection diodes used in TVS applications. SADs see a temperature increase as voltage resistance increases, whereas Zener diodes see a temperature increase as voltage resistance decreases.
Zener Diode: It is an electronic component which allows the current to flow in forward bias as well as reverse bias direction.This breakdown voltage is known as the Zener voltage. In a standard diode, the Zener voltage is high, and the diode is permanently damaged if a reverse current above that value is allowed to pass through it. Zener diodes are designed in a way where the Zener voltage is a much lower value. There is a controlled breakdown which does not damage the diode when a reverse current above the Zener voltage passes through a Zener diode.
Schottky diode: It is an electronic component which has less forward voltage drop than the PN junction. It is also known as barrier diode.When a p-type semiconductor is joined with an n-type semiconductor, a junction is formed between the P-type and N-type semiconductor. This junction is known as P-N junction. In schottky diode, metals such as aluminum or platinum replace the P-type semiconductor.Schottky diode can switch on and off much faster than the p-n junction diode. Also, the schottky diode produces less unwanted noise than p-n junction diode.
Step recovery diode( SRD): It is an electronic component which can generate short pulses.The main phenomenon used in SRDs is the storage of electric charge during forward conduction, which is present in all semiconductor junction diodes and is due to finite lifetime of minority carriers in semiconductors. The diode is also capable of working at moderate power levels, and this gives it a distinct advantage over some other radio frequency technologies that are available.
Tunnel diode: It is a semiconductor electronic device that able to do fast operations.A Tunnel diode is a heavily doped p-n junction diode in which the electric current decreases as the voltage increases.In tunnel diode, electric current is caused by “Tunneling”. The tunnel diode is used as a very fast switching device in computers. It is also used in high-frequency oscillators and amplifiers.
Varactor diode: A varactor diode is a special kind of diode and widely used in electronics industries.The varactor diode is a solid semiconductor microwave used in variable capacitance controlling voltage.These diodes are also named as varicap diodes. Even though the outcome of the variable capacitance can be showed by the normal P-N junction diodes, but these diodes are chosen for giving the desired capacitance changes as they are special types of diodes. Varactor diodes are specifically fabricated and optimized such that they permits a high range of changes in capacitance.
Laser diode:Laser is a narrow beam of Photons emitted with very high intensity of light. Laser diodes are used in optical fiber systems, compact disc players, laser printers, remote-control devices, and intrusion detection systems.Laser diodes differ from conventional lasers, such as the helium-neon (He-Ne), ruby, and gas. A laser diode, also known as an injection laser or diode laser.
Vaccum diode: A Vacuum tube diode is a two electrode vacuumtube as its name shows DI for two ODE for electrodes. Vaccum diode consists of two electrodes ( cathode & anode) or plate. The cathode emits the free electrons,so it is called as emitter. The anode collects the free electrons,so it is called as collector.
Point-contact diode: POINT-CONTACT DIODES are usually known as CRYSTALS, the point-contact diode depends on the pressure of contact between a point and a semiconductor crystal. These diodes are used in many applications like a crystal radio receiver. A crystal diode is also called as a Cat’s-whisker diode.
Gunn diode: Gunn diode is also known as transferred electron devices(TED).Its largest use is in electronic oscillators to generate microwaves, in applications such as radar speed guns, microwave relay data link transmitters, and automatic door openers. The Gunn diode operation depends on the fact that it has a voltage-controlled negative resistance.It RF frequencies between 1 and 100 GHz.
Peltier diode: Peltier diode are heat pumps that transfer heat from one side to the other, depending on the direction of the electrical current, Such an instrument is also called a thermoelectric cooler (TEC).The TEC inside the laser Butterfly package, in the figure above, is a Peltier diode. The laser will actually be mounted on top of the Peltier cooler in order to maintain a constant temperature for the laser, regardless of the ambient temperature.
2) What is a transistor?
A transistor is a miniature electronic component that can do two different jobs. It can work either as an amplifier or a switch, When it works as an amplifier, it takes in a tiny electric current at one end and produces a much bigger electric current.
Symbol used for Transistors
Types of Transistors
- Bipolar Junction Transistor(BJT)
- Field Effect Transistor(FET)
- n-p-n Transistor & p-n-p Transistor
- Junction Field Effect Transistor(JFET)
- Heterojunction Bipolar Transistor(HBT)
- Darlington Transistor
- Metal–oxide–semiconductor field-effect transistor(MOSFET)
Bipolar Junction Transistor(BJT)
Bipolar Junction Transistor (BJT) is generally called a Junction transistor.The BJT transistors have three terminals named emitter (E), Base (B), Collector (C). The name itself indicates that it has two junctions between p-type and n-type semiconductors. The BJT transistors are classified into NPN and PNP transistors depending on the construction.
Bipolar junction transistors can operate in three regions, they are
- Cut-off Region: Here the transistor is in ‘OFF’ state i.e the current flowing through the transistor is zero.
- Active Region: Here the transistor acts as an amplifier.
- Saturation Region: Here the transistor is in fully ‘ON’ state and also works as a closed switch.
The Field-Effect-Transistor (FET)
Field Effect Transistor(FET) is another transistor type. Basically, the FET transistors have three terminals they are gate (G), Drain (D), and Source (S). The FET transistors are uni-polar transistors because they perform single-channel operation whereas BJT transistors are bipolar junction transistors. The FET transistors have high current gain than BJT transistors.
NPN is one of the two types of Bipolar Junction Transistors (BJT). The NPN transistor consists of two n-type semiconductor materials and they are separated by a thin layer of p-type semiconductor. Here the majority charge carriers are electrons and holes are the minority charge carriers. The flowing of electrons from emitter to collector forms the current flow in the transistor through the base terminal.
The PNP is another type of Bipolar Junction Transistors (BJT). The PNP transistors contain two p-type semiconductor materials and are separated by a thin layer of n-type semiconductor. The majority charge carriers in the PNP transistors are holes and electrons are minority charge carriers. The arrow in the emitter terminal of transistor indicates the flow of conventional current. In PNP transistor the current flows from Emitter to Collector.
Junction Field Effect Transistor(JFET)
The Junction-Field-Effect transistor (JFET) is an earliest and simple type of FET transistors. These JFETs are used as switches, amplifiers, and resistors. This transistor is a voltage-controlled device. It doesn’t need any biasing current. The JFET transistors are available in both N-channel and P-channel types.
Heterojunction Bipolar Transistor(HBT)
Heterojunction bipolar transistors are bipolar junction transistors, which are composed of at least two different semiconductors. The energy bandgap as well as all other material properties can be different in the emitter, base and collector.
A Darlington transistor, also known as a Darlington pair, consists of a pair of bipolar transistors that are connected in order to provide a very high-current gain from a low-base current. In a Darlington transistor, the input transistor’s emitter is wired to the output transistor’s base and their collectors are tied together. Therefore, the current that is amplified by the input transistor is amplified even further by the output transistor.
Metal–oxide–semiconductor field-effect transistor(MOSFET)
MOSFET is a special type of field-effect transistor that works by electronically varying the width of a channel along which charge carriers ( electrons or holes) flow. The wider the channel, the better the device conducts. The charge carriers enter the channel at the source, and exit via the drain . The width of the channel is controlled by the voltage on an electrode called the gate , which is located physically between the source and the drain and is insulated from the channel by an extremely thin layer of metal oxide.
3)What is a Capacitor?
A capacitor was historically first known as an electric condenser. A capacitor is a passive two-terminal electrical component that stores electrical energy in an electric field. The effect of a capacitor is known as capacitance. While capacitance exists between any two electrical conductors of a circuit in sufficiently close proximity, a capacitor is specifically designed to provide and enhance this effect for a variety of practical applications by consideration of size, shape, and positioning of closely spaced conductors, and the intervening dielectric material.
Symbol used for Capacitors
Types of Capacitor
- Ceramic capacitor
- Electrolytic capacitor
- Tantalum capacitor
- Silver Mica Capacitor
- Polystyrene Film Capacitor
- Polyester Film Capacitor
- Polycarbonate capacitor
- Polypropylene Capacitor
- Glass Dielectric capacitors
The ceramic capacitor is a type of capacitor that is used in many applications from audio to RF. Values range from a few picofarads to around 0.1 microfarads. Ceramic capacitor types are by far the most commonly used type of capacitor being cheap and reliable and their loss factor is particularly low although this is dependent on the exact dielectric in use.
Electrolytic capacitors are a type of capacitor that is polarised. They are able to offer high capacitance values – typically above 1μF, and are most widely used for low-frequency applications – power supplies, decoupling and audio coupling applications as they have a frequency limit if around 100 kHz.
Like electrolytic capacitors, tantalum capacitors are also polarised and offer a very high capacitance level for their volume. However, this type of capacitor is very intolerant of being reversely biased, often exploding when placed under stress. This type of capacitor must also not be subject to high ripple currents or voltages above their working voltage. They are available in both led and surface mount formats.
Silver Mica Capacitor
Silver mica capacitors are not as widely used these days, but they still offer very high levels of stability, low loss, and accuracy where space is not an issue. They are primarily used for RF applications and they are limited to maximum values of 1000 pF.
Polystyrene Film Capacitor
Polystyrene capacitors are a relatively cheap form of capacitor but offer a close tolerance capacitor where needed. They are tubular in shape resulting from the fact that the plate / dielectric sandwich is rolled together, but this adds inductance limiting their frequency response to a few hundred kHz. They are generally only available as leaded electronics components.
Polyester Film Capacitor
Polyester film capacitors are used where cost is a consideration as they do not offer a high tolerance. Many polyester film capacitors have a tolerance of 5% or 10%, which is adequate for many applications. They are generally only available as leaded electronics components.
The polycarbonate capacitors have been used in applications where reliability and performance are critical. The polycarbonate film is very stable and enables high tolerance capacitors to be made which will hold their capacitance value over time. In addition, they have a low dissipation factor, and they remain stable over a wide temperature range, many being specified from -55°C to +125°C.
The polypropylene capacitor is sometimes used when a higher tolerance type of capacitor is necessary than polyester capacitors offer. As the name implies, this capacitor uses a polypropylene film for the dielectric. One of the advantages of the capacitor is that there is very little chance of capacitance with time and voltage applied. This type of capacitor is also used for low frequencies, with 100 kHz or so being the upper limit. They are generally only available as leaded electronics components.
Glass Dielectric capacitors
As the name implies, this capacitor type uses glass as the dielectric. Although expensive, these capacitors offer very high levels or performance in terms of extremely low loss, high RF current capability, no piezo-electric noise and other features making them ideal for many performance RF applications.
4)What is Resistor?
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.
Resistors are used for many purposes. A few examples include delimit electric current, voltage division, heat generation, matching and loading circuits, control gain, and fix time constants. They are commercially available with resistance values over a range of more than nine orders of magnitude. They can be used to as electric brakes to dissipate kinetic energy from trains or be smaller than a square millimeter for electronics.
The symbol used for Resistors
- Linear Resistors
- Non-Linear Resistors
Linear resistors are those in which currently produced is directly proportional to the applied voltage. Their current versus applied voltage is straight and linear or we can say that their resistance remains constant.
There are two types of resistors which have linear properties:-
- Fixed Resistors
- Variable Resistors
A fixed resistor is a resistor that has a specific value and we can’t change the value of fixed resistors.
Types of Fixed resistors.
- Carbon Composition Resistors
- Wire Wound Resistors
- Thin Film Resistors
- Thick Film Resistors
1) Carbon Composition Resistors
2) Wire-wound Resistors
3) Thin Film Resistors
All thin film resistors are made from high grid ceramic rod and resistive material.
There are two types of thin-film resistors:-
3.2. Metal Film Resistors
3.1.Carbon Film Resistors
Carbon Film resistors contain an insulating material rod or core made of high-grade ceramic material which is called the substrate. A very thin resistive carbon layer or film overlaid around the rod. These kinds of resistors are widely used in electronic circuits because of negligible noise and wide operating range and stability as compared to solid carbon resistors.
The value may reach several µH, although uncut resistors are available and the level of self-induction for these components can be around 0.01 µH. The capacitance may be around 0.5pF.
3.2. Metal Film Resistors
Metal film resistors are the same in construction like Carbon film resistors, but the main difference is that there is metal (or a mixture of metal oxides, Nickel Chromium, or a mixture of metals and glass which is called metal glaze which is used as resistive film) instead of carbon.
Their temperature coefficient is very low (±2 ppm/°C) and used where stability and low noise level is important. Compared to wirewound or carbon composition resistors, these resistors are easier damaged by voltage surges and power overloads.
4) Thick Film Resistors
1. Metal Oxide Resistors
2. Cermet Film Resistors
3. Fusible Resistors
4.1) Metal Oxide Resistors
The metal oxide film resistors have poor properties for low values and tolerance. The temperature coefficient is around 300 ppm/°C, which is higher than for metal film types.
4.2) Cermet Oxide Resistors
4.3) Fusible Resistors
These kinds of resistors are the same as a wire wound resistor. When a circuit power rating increased than the specified value, then this resistor is fused, i.e. it breaks or opens the circuit. That’s why it is called Fusible resistors.
A resistor of which the ohmic resistance value can be adjusted. Either mechanically or electronically. They are used in the radio receiver for volume control and tone control resistance. It can be used as a three-terminal as well as a two-terminal device. Mostly they are used as a three-terminal device. Variable resistors are mostly used for device calibration.
The potentiometer is a three-terminal device that is used for controlling the level of voltage in the circuit. It is defined as “A potentiometer is a manually adjustable, variable resistor with three terminals. Two terminals are connected to a resistive element, the third terminal is connected to an adjustable wiper. The position of the wiper determines the output voltage”.
A potentiometer is also commonly known as a potmeter or pot. The most common form of potmeter is the single turn rotary potmeter. This type of pot is often used in audio volume control (logarithmic taper) as well as many other applications. Different materials are used to construct potentiometers, including carbon composition, cermet, wirewound, conductive plastic or metal film.
Fig: Types of Potentiometer
Symbols used for Potentiometer
Rheostats are a two or three-terminal device that is used for the current limiting purpose by hand or manual operation. Rheostats are also known as tapped resistors or variable wire wound resistors. It is used to control the electrical resistance of a circuit without interrupting the flow of current. Rheostat has 3 terminals and usually consists of a resistive wire wrapped to form a toroid coil with a wiper that slides along the surface of the coil. It is most often designed with a ceramic core. Rheostats are used in applications that require high voltage and current.
Fig: Different types of Rheostats
The most common uses today for rheostats are as light dimmers and motor speed controls. They are often used in arc lamps, pumps, fans and blowers, respirators, dental and medical equipment, and model trains.
The symbol used for Rheostat
There is an additional screw with Potentiometer or variable resistors for better efficiency and operation and they are known as Trimmers. A trimmer is a miniature adjustable electrical component. They are adjusted to the right position during the alignment procedure of the receiver. Trimmers come in a variety of sizes and levels of precision. For example, multi-turn trim potentiometers exist, in which it takes several turns of the adjustment screw to reach the end value. This allows for very high degrees of accuracy.
They are made from carbon composition, carbon film, cermet, and wire materials and available in the range of 50 Ohms up to 5 megaohms. The power rating of Trimmers potentiometers is from 1/3 to ¾ Watts.
The symbol used for Trimmer
2. Non-Linear Resistors
2. Varistors (VDR)
3. Photo Resistor or Photo Conductive Cell or LDR
Thermisters is a two-terminal device which is very sensitive to temperature. In other words, Thermisters is a type of variable resistor that notices the change in temperature. Thermisters are made from the cobalt, Nickel, Strontium and the metal oxides of Manganese.
The symbol used for thermistor
2.2) Varistors (VDR)
A varistor is an electronic component with an electrical resistance that varies with the applied voltage. Also known as a voltage-dependent resistor (VDR), it has a nonlinear, non-ohmic current-voltage characteristic that is similar to that of a diode. In contrast to a diode, however, it has the same characteristic for both directions of traversing current. At low voltage, it has a high electrical resistance which decreases as the voltage is raised.
Other important parameters are the varistor’s energy rating in joules, operating voltage, response time, maximum current, and breakdown (clamping) voltage. The energy rating is often defined using standardized transients such as 8/20 microseconds or 10/1000 microseconds, where 8 microseconds is the transient’s front time and 20 microseconds is the time to half value.
The symbol used for Varistor
2.3) Photo Resistor or Photo Conductive Cell or LDR (Light Dependent Resistors)
Photo Resistor or LDR (Light Dependent Resistors) is a resistor whose terminal value of resistance changes with light intensity. In other words, those resistors, in which resistance values change with the falling light on their surface is called Photo Resistor or Photo Conductive Cell or LDR (Light Dependent Resistor). The material which is used to make these kinds of resistors is called photoconductors, e.g. cadmium sulfide, lead sulfide etc.
When light falls on the photoconductive cells (LDR or Photoresistor), then there is an increase in the free carriers (electron-hole pairs) due to light energy, which reduces the resistance of semiconductor material (i.e. the quantity of light energy is inversely proportional to the semiconductor material). It means photoresistors have a negative temperature coefficient.
Symbol used for LDR
Applications of Resistor
- Current control and limiting.
- To change electrical energy in the form of heat energy.
- As a shunt in Ampere meters.
- As a multiplier in a Voltmeter.
- To control the temperature.
- To control voltage or Drop.
- For protection purposes, e.g. Fusible Resistors.
- In laboratories.
- In-home elemechanically critical appliances like heater, iron, immersion rod, etc.
- Widely used in the electronics industries.
Resistor color code
The Standard Resistor Colour Code Chart.
A resistor colored Yellow-Violet-Orange-Gold would be 47 kΩ with a tolerance of +/- 5%.
5) what is the printed circuit board(PCB)?
A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. Components (e.g. capacitors, resistors, or active devices) are generally soldered on the PCB. Advanced PCBs may contain components embedded in the substrate. If the PCB itself is green, that indicates, that its made from glass-epoxy which is naturally green. Also, your PCB could be made in every single color that exists. The finishing color is usually a solder mask. This mask is applied for safety reasons, for preventing eventual short circuits and etc.
6) what is breadboard?
A breadboard is a construction base for prototyping of electronics. Originally it was literally a breadboard, a polished piece of wood used for slicing bread. An electronics breadboard (as opposed to the type on which sandwiches are made) is actually referring to a solderless breadboard. These are great units for making temporary circuits and prototyping, and they require absolutely no soldering. When building your circuit, you are not confined to stay on just one breadboard. Some circuits will require a lot more space. Many breadboards have little nubbins and slots on the sides, and some even have them on the tops and bottoms. These allow you to connect multiple breadboards together to form the ultimate prototyping surface.
So, Friends, I hope you understand this topic very well. In the upcoming Tutorial, I will be back with some new interesting Projects and we will discuss some useful development topics. Here if you want to recommend that what I should write in the upcoming Tutorial then please leave your comments. and if u need any help or query please don’t hesitate to discuss it with me. Thank You 🙂