Wednesday, December 29, 2010
Wednesday, December 8, 2010
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Monday, December 6, 2010
Types of Electronics
Electronics field can be divided into two groups on the basis of circuits and components. They are: analog and digital. A particular device may consist of circuitry that has one or the other or a mix of the two types.
Analog circuits
Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits.
The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.
Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.
One rarely finds modern circuits that are entirely analog. These days analog circuitry may use digital or even microprocessor techniques to improve performance. This type of circuit is usually called "mixed signal" rather than analog or digital.
Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation. An example is the comparator which takes in a continuous range of voltage but only outputs one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch having essentially two levels of output.
Digital circuits
Digital circuits are electric circuits based on a number of discrete voltage levels. Digital circuits are the most common physical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. Most digital circuits use two voltage levels labeled "Low"(0) and "High"(1). Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use. Ternary (with three states) logic has been studied, and some prototype computers made.
Computers, electronic clocks, and programmable logic controllers (used to control industrial processes) are constructed of digital circuits. Digital Signal Processors are another example.
References
1. IEEE Dictionary of Electrical and Electronics Terms ISBN 978-0-471-42806-0
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals. It is made of a solid piece of semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current flowing through another pair of terminals. Because the controlled (output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal.
The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Following its release in the early 1950s the transistor revolutionised the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, amongst other things.
Importance
The transistor is the key active component in practically all modern electronics, and is considered by many to be one of the greatest inventions of the twentieth century. Its importance in today's society rests on its ability to be mass produced using a highly automated process (semiconductor device fabrication) that achieves astonishingly low per-transistor costs.
The transistor's low cost, flexibility, and reliability have made it a ubiquitous device. Transistorized mechatronic circuits have replaced electromechanical devices in controlling appliances and machinery
Usage
The bipolar junction transistor, or BJT, was the most commonly used transistor in the 1960s and 70s. Even after MOSFETs became widely available, the BJT remained the transistor of choice for many analog circuits such as simple amplifiers because of their greater linearity and ease of manufacture. Desirable properties of MOSFETs, such as their utility in low-power devices, usually in the CMOS configuration, allowed them to capture nearly all market share for digital circuits; more recently MOSFETs have captured most analog and power applications as well, including modern clocked analog circuits, voltage regulators, amplifiers, power transmitters, motor drivers, etc.
Simplified operation
The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal; that is, it can act as an amplifier. Alternatively, the transistor can be used to turn current on or off in a circuit as an electrically controlled switch, where the amount of current is determined by other circuit elements.
The two types of transistors have slight differences in how they are used in a circuit. A bipolar transistor has terminals labeled base, collector, and emitter. A small current at the base terminal (that is, flowing from the base to the emitter) can control or switch a much larger current between the collector and emitter terminals.
The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Following its release in the early 1950s the transistor revolutionised the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, amongst other things.
Importance
The transistor is the key active component in practically all modern electronics, and is considered by many to be one of the greatest inventions of the twentieth century. Its importance in today's society rests on its ability to be mass produced using a highly automated process (semiconductor device fabrication) that achieves astonishingly low per-transistor costs.
The transistor's low cost, flexibility, and reliability have made it a ubiquitous device. Transistorized mechatronic circuits have replaced electromechanical devices in controlling appliances and machinery
Usage
The bipolar junction transistor, or BJT, was the most commonly used transistor in the 1960s and 70s. Even after MOSFETs became widely available, the BJT remained the transistor of choice for many analog circuits such as simple amplifiers because of their greater linearity and ease of manufacture. Desirable properties of MOSFETs, such as their utility in low-power devices, usually in the CMOS configuration, allowed them to capture nearly all market share for digital circuits; more recently MOSFETs have captured most analog and power applications as well, including modern clocked analog circuits, voltage regulators, amplifiers, power transmitters, motor drivers, etc.
Simplified operation
The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal; that is, it can act as an amplifier. Alternatively, the transistor can be used to turn current on or off in a circuit as an electrically controlled switch, where the amount of current is determined by other circuit elements.
The two types of transistors have slight differences in how they are used in a circuit. A bipolar transistor has terminals labeled base, collector, and emitter. A small current at the base terminal (that is, flowing from the base to the emitter) can control or switch a much larger current between the collector and emitter terminals.
Materials used in electronics
Generally in the field of electronics, there are two types of material used for manufacturing the electronic devices. They are; vacuum tubes and semiconductor.
i) Vacuum tubes
During twentieth century the electronic devices were formed using tubes. The material used for manufacturing the tube was glass. The vacuum was created inside the glass and hence that device was generally called vacuum tubes in which the electrons flow through vacuum. These tubes have been finding wide applications in radio, telephones, sound motion pictures, televisions and industrials automation. A vacuum tube usually consists of a cathode for emitting electrons; an anode, for collecting electrons and one or more electrodes called grid for controlling flow of electrons cathode and anode.
According to the number of electrodes vacuum tubes are classified as;
a. Vacuum diode
b. Vacuum triode
c. Vacuum tetrode
d. Vacuum pentode
ii) Semiconductor material
A semiconductor is a material with electrical conductivity due to electron flow (as opposed to ionic conductivity) intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter. Semiconductor materials are the foundation of modern electronics, including radio, computers, telephones, and many other devices. Such devices include transistors, solar cells, many kinds of diodes including the light-emitting diode, the silicon controlled rectifier, and digital and analog integrated circuits. In a metallic conductor, current is carried by the flow of electrons. In semiconductors, current is often schematized as being carried either by the flow of electrons or by the flow of positively charged "holes" in the electron structure of the material. Actually, however, in both cases only electron movements are involved.
Common semiconducting materials are crystalline solids, but amorphous and liquid semiconductors are known. These include hydrogenated amorphous silicon and mixtures of arsenic, selenium and tellurium in a variety of proportions. Such compounds share with better known semiconductors intermediate conductivity and a rapid variation of conductivity with temperature, as well as occasional negative resistance. Such disordered materials lack the rigid crystalline structure of conventional semiconductors such as silicon and are generally used in thin film structures, which are less demanding for as concerns the electronic quality of the material and thus are relatively insensitive to impurities and radiation damage. Organic semiconductors, that is, organic materials with properties resembling conventional semiconductors, are also known.
References
Mehta V. K., Principles of Electronics, First Edition, S. Chand & Company LTD., [2002]
Sedra and Smith, Microelectronic Circuits, Fourth Edition, Oxford University Press Inc, UK, [1998]
IEEE Dictionary of Electrical and Electronics Terms ISBN 978-0-471-42806-0
Introduction of Electronics
In this fast developing society, electronics has come to stay as the most important branch of engineering. Electronics devices are being used in almost all the industries for quality control and automation and they are fast replacing the present vast army of workers engaged in processing and assembling in the factories.
The rapid growth of electronics technology offers a formidable challenge to the beginner, who may be almost paralyzed by the mass of details. Great strikes taken in the industrial application of electronics during the recent years have demonstrated that this versatile tool can be of great importance in increasing production, efficiency and control.
Electronics is the branch of engineering which deals with current conduction through a vacuum of gas or semiconductor.
Electronics essentially deals with electronic devices and their utilization. An electronic device is that in which current flows through a vacuum or gas or semiconductor. Such devices have valuable properties which enable them to function and behave as the friend of man today.
Electronics has gained much importance due to its numerous applications in industry. Some important applications of electronics are as follow.
i) Rectification
The conversion of a.c. into d.c. is called rectification. Electronic devices can convert a.c. power into d.c. power with very high efficiency.
ii) Amplification
It is the most important application of electronic devices. The process of raising the strength of the weak signal is known as amplification. Amplifier is used for this purpose. Amplifier is used in radio-set where the weak signal is amplified so that it can be heard loudly. Amplifiers are also used in television, public address system etc.
iii) Control
Electronic devices find wide application in automatic control. For example, speed of motor, voltage across the refrigerator etc. can automatically be controlled with the help of such devices.
iv) Generation
Electronic devices can convert d.c. power into a.c. power of any frequency. When performing this function, they are known as oscillators. The oscillators are used in wide variety of ways. For example, electronic high frequency heating is used for annealing and hardening.
v) Conversion of light into electricity and vice versa
Electronic devices can convert light into electricity. This process is known as photo electricity. Photo electric devices are used in Burglar alarms, sound recording on motion pictures etc.
Such devices can also convert electricity into light. This valuable property is utilized in television and radar.
References
Mehta V. K., Principles of Electronics, First Edition, S. Chand & Company LTD., [2002]
Sedra and Smith, Microelectronic Circuits, Fourth Edition, Oxford University Press Inc, UK, [1998]
Integrated Electronic Circuit
In electronics, an integrated circuit (also known as IC, chip, or microchip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as passive components) that has been manufactured in the surface of a thin substrate of semiconductor material. Integrated circuits are used in almost all electronic equipment in use today and have revolutionized the world of electronics. Computers, cellular phones, and other digital appliances are now inextricable parts of the structure of modern societies, made possible by the low cost of production of integrated circuits.
A hybrid integrated circuit is a miniaturized electronic circuit constructed of individual semiconductor devices, as well as passive components, bonded to a substrate or circuit board. A monolithic integrated circuit is made of devices manufactured by diffusion of trace elements into a single piece of semiconductor substrate, a chip.
Integrated circuits were made possible by experimental discoveries which showed that semiconductor devices could perform the functions of vacuum tubes and by mid-20th-century technology advancements in semiconductor device fabrication. The integration of large numbers of tiny transistors into a small chip was an enormous improvement over the manual assembly of circuits using electronic components. The integrated circuit's mass production capability, reliability, and building-block approach to circuit design ensured the rapid adoption of standardized ICs in place of designs using discrete transistors.
There are two main advantages of ICs over discrete circuits: cost and performance. Cost is low because the chips, with all their components, are printed as a unit by photolithography rather than being constructed one transistor at a time. Furthermore, much less material is used to construct a packaged IC die than a discrete circuit. Performance is high since the components switch quickly and consume little power (compared to their discrete counterparts) because the components are small and positioned close together.
Advances in integrated circuits
Among the most advanced integrated circuits are the microprocessors or "cores", which control everything from computers and cellular phones to digital microwave ovens. Digital memory chips and ASICs are examples of other families of integrated circuits that are important to the modern information society. While the cost of designing and developing a complex integrated circuit is quite high, when spread across typically millions of production units the individual IC cost is minimized. The performance of ICs is high because the small size allows short traces which in turn allows low power logic (such as CMOS) to be used at fast switching speeds.
Classification
Integrated circuits can be classified into analog, digital and mixed signal (both analog and digital on the same chip).
Digital integrated circuits can contain anything from one to millions of logic gates, flip-flops, multiplexers, and other circuits in a few square millimeters. The small size of these circuits allows high speed, low power dissipation, and reduced manufacturing cost compared with board-level integration.
Analog ICs, such as sensors, power management circuits, and operational amplifiers, work by processing continuous signals. They perform functions like amplification, active filtering, demodulation, mixing, etc. Analog ICs ease the burden on circuit designers by having expertly designed analog circuits available instead of designing a difficult analog circuit from scratch.
References
Baker, R. J. (2010). CMOS: Circuit Design, Layout, and Simulation, Third Edition. Wiley-IEEE. ISBN 978-0-470-88132-3.
Hodges, D.A., Jackson H.G., and Saleh, R. (2003). Analysis and Design of Digital Integrated Circuits. McGraw-Hill. ISBN 0-07-228365-3.
Rabaey, J.M., Chandrakasan, A., and Nikolic, B. (2003). Digital Integrated Circuits, 2nd Edition. ISBN 0-13-090996-3
Electronics
Electronics is the branch of science and technology which makes use of the controlled motion of electrons through different media. The ability to control electron flow is usually applied to information handling or device control. Electronics is distinct from electrical science and technology, which deals with the generation, distribution, control and application of electrical power. This distinction started around 1906 with the invention by Lee De Forest of the triode, which made electrical amplification possible with a non-mechanical device. Until 1950 this field was called "radio technology" because its principal application was the design and theory of radio transmitters, receivers and vacuum tubes.
Most electronic devices today use semiconductor components to perform electron control. The study of semiconductor devices and related technology is considered a branch of physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering. This article focuses on engineering aspects of electronics.
An electronic component is any physical entity in an electronic system used to affect the electrons or their associated fields in a desired manner consistent with the intended function of the electronic system. Components are generally intended to be connected together, usually by being soldered to a printed circuit board (PCB), to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Components may be packaged singly or in more complex groups as integrated circuits. Some common electronic components are capacitors, inductors, resistors, diodes, transistors, etc. Components are often categorized as active (e.g. transistors and thyristors) or passive (e.g. resistors and capacitors).
References
1. IEEE Dictionary of Electrical and Electronics Terms ISBN 978-0-471-42806-0
Most electronic devices today use semiconductor components to perform electron control. The study of semiconductor devices and related technology is considered a branch of physics, whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering. This article focuses on engineering aspects of electronics.
An electronic component is any physical entity in an electronic system used to affect the electrons or their associated fields in a desired manner consistent with the intended function of the electronic system. Components are generally intended to be connected together, usually by being soldered to a printed circuit board (PCB), to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Components may be packaged singly or in more complex groups as integrated circuits. Some common electronic components are capacitors, inductors, resistors, diodes, transistors, etc. Components are often categorized as active (e.g. transistors and thyristors) or passive (e.g. resistors and capacitors).
References
1. IEEE Dictionary of Electrical and Electronics Terms ISBN 978-0-471-42806-0
Electronic music
Electronic music is music that employs electronic musical instruments and electronic music technology in its production. In general a distinction can be made between sound produced using electromechanical means and that produced using electronic technology. Examples of electromechanical sound producing devices include the telharmonium, Hammond organ, and the electric guitar. Purely electronic sound production can be achieved using devices such as the Theremin, sound synthesizer, and computer.
Electronic music was once associated almost exclusively with Western art music but from the late 1960s on the availability of affordable music technology meant that music produced using electronic means became increasingly common in the popular domain. Today electronic music includes many varieties and ranges from experimental art music to popular forms such as electronic dance music.
The ability to record sounds is often connected to the production of electronic music, but not absolutely necessary for it. The earliest known sound recording device was the phonautograph, patented in 1857 by Édouard-Léon Scott de Martinville. It could record sounds visually, but was not meant to play them back.
In 1878, Thomas A. Edison patented the phonograph, which used cylinders similar to Scott's device. Although cylinders continued in use for some time, Emile Berliner developed the disc phonograph in 1887. A significant invention, which was later to have a profound effect on electronic music, was Lee DeForest's triode audion. This was the first thermionic valve, or vacuum tube, invented in 1906, which led to the generation and amplification of electrical signals, radio broadcasting, and electronic computation, amongst other things.
Before electronic music, there was a growing desire for composers to use emerging technologies for musical purposes. Several instruments were created that employed electromechanical designs and they paved the way for the later emergence of electronic instruments. An electromechanical instrument called the Telharmonium (sometimes Teleharmonium or Dynamophone) was developed by Thaddeus Cahill in the years 1898-1912. However, simple inconvenience hindered the adoption of the Telharmonium, due to its immense size. The first electronic instrument is often viewed to be the Theremin, invented by Professor Léon Theremin circa 1919–1920. Another early electronic instrument was the Ondes Martenot, which was most famously used in the Turangalîla-Symphonie by Olivier Messiaen as well as other works by him. It was also used by other, pIn 1907, just a year later after the invention of the triode audion, Ferruccio Busoni published Sketch of a New Esthetic of Music, which discussed the use of electrical and other new sound sources in future music. He wrote of the future of microtonal scales in music, made possible by Cahill's Dynamophone: "Only a long and careful series of experiments, and a continued training of the ear, can render this unfamiliar material approachable and plastic for the coming generation, and for Art."rimarily French, composers such as Andre Jolivet.
Electronic music was once associated almost exclusively with Western art music but from the late 1960s on the availability of affordable music technology meant that music produced using electronic means became increasingly common in the popular domain. Today electronic music includes many varieties and ranges from experimental art music to popular forms such as electronic dance music.
The ability to record sounds is often connected to the production of electronic music, but not absolutely necessary for it. The earliest known sound recording device was the phonautograph, patented in 1857 by Édouard-Léon Scott de Martinville. It could record sounds visually, but was not meant to play them back.
In 1878, Thomas A. Edison patented the phonograph, which used cylinders similar to Scott's device. Although cylinders continued in use for some time, Emile Berliner developed the disc phonograph in 1887. A significant invention, which was later to have a profound effect on electronic music, was Lee DeForest's triode audion. This was the first thermionic valve, or vacuum tube, invented in 1906, which led to the generation and amplification of electrical signals, radio broadcasting, and electronic computation, amongst other things.
Before electronic music, there was a growing desire for composers to use emerging technologies for musical purposes. Several instruments were created that employed electromechanical designs and they paved the way for the later emergence of electronic instruments. An electromechanical instrument called the Telharmonium (sometimes Teleharmonium or Dynamophone) was developed by Thaddeus Cahill in the years 1898-1912. However, simple inconvenience hindered the adoption of the Telharmonium, due to its immense size. The first electronic instrument is often viewed to be the Theremin, invented by Professor Léon Theremin circa 1919–1920. Another early electronic instrument was the Ondes Martenot, which was most famously used in the Turangalîla-Symphonie by Olivier Messiaen as well as other works by him. It was also used by other, pIn 1907, just a year later after the invention of the triode audion, Ferruccio Busoni published Sketch of a New Esthetic of Music, which discussed the use of electrical and other new sound sources in future music. He wrote of the future of microtonal scales in music, made possible by Cahill's Dynamophone: "Only a long and careful series of experiments, and a continued training of the ear, can render this unfamiliar material approachable and plastic for the coming generation, and for Art."rimarily French, composers such as Andre Jolivet.
Electronic color code
The electronic color code discussed here is used to indicate the values or ratings of electronic components, very commonly for resistors, but also for capacitors, inductors, and others. A separate code, the 25-pair color code, is used to identify wires in some telecommunications cables.
The electronic color code was developed in the early 1920s by the Radio Manufacturer's Association.
Colorbands were commonly used (especially on resistors) because they were easily printed on tiny components, decreasing construction costs. However, there were drawbacks, especially for color blind people. Overheating of a component, or dirt accumulation, may make it impossible to distinguish brown from red from orange. Advances in printing technology have made printed numbers practical for small components, which are often found in modern electronics. Resistor, capacitor and inductor
It is sometimes not obvious whether a color coded component is a resistor, capacitor, or inductor, and this may be deduced by knowledge of its circuit function, physical shape or by measurement (capacitors have nearly infinite resistance; unfortunately, so do faulty open-circuit resistors and inductors).
Resistor values are always coded in ohms, capacitors in picofarads (pF), and inductors in microhenries (µH).
· band A is first significant figure of component value
· band B is the second significant figure
· band C is the decimal multiplier
· band D if present, indicates tolerance of value in percent (no color means 20%)
For example, a resistor with bands of yellow, violet, red, and gold will have first digit 4 (yellow in table below), second digit 7 (violet), followed by 2 (red) zeros: 4,700 ohms. Gold signifies that the tolerance is ±5%, so the real resistance could lie anywhere between 4,465 and 4,935 ohms.
Resistors manufactured for military use may also include a fifth band which indicates component failure rate (reliability);
Tight tolerance resistors may have three bands for significant figures rather than two, and/or an additional band indicating temperature coefficient, in units of ppm/K.
All coded components will have at least two value bands and a multiplier; other bands are optional (italicised below).
The standard color code per EN 60062:2005 is as follows:
Color Significant
figures Multiplier Tolerance Temp. Coefficient (ppm/K)
Black 0 ×100 – 250 U
Brown 1 ×101 ±1% F 100 S
Red 2 ×102 ±2% G 50 R
Orange 3 ×103 – 15 P
Yellow 4 ×104 – 25 Q
Green 5 ×105 ±0.5% D 20 Z
Blue 6 ×106 ±0.25% C 10 Z
Violet 7 ×107 ±0.1% B 5 M
Gray 8 ×108 ±0.05% A 1 K
White 9 ×109 – –
Gold – ×10-1 ±5% J –
Silver – ×10-2 ±10% K –
None – – ±20% M –
1. Any temperature coefficients not assigned its own letter shall be marked "Z", and the coefficient found in other documentation.
As an example, let us take a resistor which (read left to right) displays the colors yellow, violet, yellow, brown. We take the first two bands as the value, giving us 4, 7. Then the third band, another yellow, gives us the multiplier 104. Our total value is then 47 x 104 Ω, totalling 470,000 Ω or 470 kΩ. Our brown is then a tolerance of ±1%.
Resistors use specific values, which are determined by their tolerance. These values repeat for every order of magnitude; 6.8, 68, 680, and so forth. This is useful because the digits, and hence the first two or three stripes, will always be similar patterns of colors, which make them easier to understand.
Zero ohm resistors are manufactured; these are lengths of wire wrapped in a resistor-shaped body which can be substituted for another resistor value in automatic insertion equipment. They are marked with a single black band.
The 'body-end-dot' or 'body-tip-spot' system was used for radial-lead composition resistors sometimes found in vacuum-tube equipment; the first band was given by the body color, the second band by the color of the end of the resistor, and the multiplier by a dot or band around the middle of the resistor. The other end of the resistor was colored gold or silver to give the tolerance, otherwise it was 20%.
Extra bands on ceramic capacitors will identify the voltage rating class and temperature coefficient characteristics. A broad black band was applied to some tubular paper capacitors to indicate the end that had the outer electrode; this allowed this end to be connected to chassis ground to provide some shielding against hum and noise pickup.
Polyester film and "gum drop" tantalum electrolytic capacitors are also color coded to give the value, working voltage and tolerance.
Diode part number
The part number for diodes was sometimes also encoded as colored rings around the diode, using the same numerals as for other parts. The JEDEC "1N" prefix was assumed, and the balance of the part number was given by three or four rings.
Postage stamp capacitors and war standard coding
Capacitors of the rectangular 'postage stamp" form made for military use during World War II used American War Standard (AWS) or Joint Army Navy (JAN) coding in six dots stamped on the capacitor. An arrow on the top row of dots pointed to the right, indicating the reading order. From left to right the top dots were: black, indicating JAN mica or silver indicating AWS paper. first and second significant figures. The bottom three dots indicated temperature characteristic, tolerance, and decimal multiplier. The characteristic was black for +/- 1000 ppm/ degree c, brown for 500, red for 200, orange for 100, yellow for -20 to +1-- ppm/ degree c, and green for 0 to +70 ppm/degree C. A similar six-dot code by EIA had the top row as first, second and third significant digits and the bottom row as voltage rating (in hundreds of volts - no color indicated 500 volts), tolerance, and multiplier. A three-dot EIA code was used for 500 volt 20% tolerance capacitors, and the dots signified first and second significant digits and the multiplier. Such capacitors were common in vacuum tube equipment and in surplus for a generation after the war but are unavailable now.
Mnemonics
A useful mnemonic matches the first letter of the color code, by order of increasing magnitude. There are many variations:
· Badly Burnt Resistors On Your Ground Bus Void General Warranties
· Better Build Roof Over Your Garage Before Vehicle Gets Wet
· Boys better remember our young girls become very good wives.. BYU Engineering Department
· Bad boys rape our young girls behind victory garden walls.
· Bad boys rape 'onest young girls but virgins go without.
· Bad boys run our young girls behind victory garden walls.
· Bad boys rape our young girls but Violet gives willingly.
· Big boys race our young girls but Violet generally wins.
The tolerance codes, gold, silver, and none, are not usually included in the mnemonics; one extension that includes them is:
· Bad beer rots our young guts but vodka goes well – get some now.
Since B can stand for both "black" and "brown", variations are formed such as "Black boys rape our young girls...".
A politically-correct mnemonic that has attained some traction in recent years is:
· Big brown rabbits often yield great big vocal groans when gingerly slapped.
Another mnemonic that is not offensive and can be used in the classroom is:
· B. B. ROY of Great Britain has Very Good Wife.
Other mnemonics commonly taught in UK engineering courses include:
· Bye Bye Rosie Off You Go Birmingham Via Great Western
· Bye Bye Rosie Off You Go Bristol Via Great Western
· Bye Bye Rosie Off You Go But Via Great Western
· Bye Bye Rosie Off You Go do Become a Very Good Wife
· Bill Brown Realized Only Yesterday Good Boys Value Good Work
The colors are sorted in the order of the visible light spectrum: red (2), orange (3), yellow (4), green (5), blue (6), violet (7). Black (0) has no energy, brown (1) has a little more, white (9) has everything and grey (8) is like white, but less intense.
Examples
Resistors color code
From top to bottom:
· Green-Blue-Brown-Black-Brown
o 560 Ω ± 1%
· Red-Red-Orange-Gold
o 22,000 Ω ± 5%
· Yellow-Violet-Brown-Gold
o 470 Ω ± 5%
· Blue-Gray-Black-Silver
o 68 Ω ± 10%
Note: The physical size of a resistor is indicative of the power it can dissipate, not of its resistance.
The electronic color code was developed in the early 1920s by the Radio Manufacturer's Association.
Colorbands were commonly used (especially on resistors) because they were easily printed on tiny components, decreasing construction costs. However, there were drawbacks, especially for color blind people. Overheating of a component, or dirt accumulation, may make it impossible to distinguish brown from red from orange. Advances in printing technology have made printed numbers practical for small components, which are often found in modern electronics. Resistor, capacitor and inductor
It is sometimes not obvious whether a color coded component is a resistor, capacitor, or inductor, and this may be deduced by knowledge of its circuit function, physical shape or by measurement (capacitors have nearly infinite resistance; unfortunately, so do faulty open-circuit resistors and inductors).
Resistor values are always coded in ohms, capacitors in picofarads (pF), and inductors in microhenries (µH).
· band A is first significant figure of component value
· band B is the second significant figure
· band C is the decimal multiplier
· band D if present, indicates tolerance of value in percent (no color means 20%)
For example, a resistor with bands of yellow, violet, red, and gold will have first digit 4 (yellow in table below), second digit 7 (violet), followed by 2 (red) zeros: 4,700 ohms. Gold signifies that the tolerance is ±5%, so the real resistance could lie anywhere between 4,465 and 4,935 ohms.
Resistors manufactured for military use may also include a fifth band which indicates component failure rate (reliability);
Tight tolerance resistors may have three bands for significant figures rather than two, and/or an additional band indicating temperature coefficient, in units of ppm/K.
All coded components will have at least two value bands and a multiplier; other bands are optional (italicised below).
The standard color code per EN 60062:2005 is as follows:
Color Significant
figures Multiplier Tolerance Temp. Coefficient (ppm/K)
Black 0 ×100 – 250 U
Brown 1 ×101 ±1% F 100 S
Red 2 ×102 ±2% G 50 R
Orange 3 ×103 – 15 P
Yellow 4 ×104 – 25 Q
Green 5 ×105 ±0.5% D 20 Z
Blue 6 ×106 ±0.25% C 10 Z
Violet 7 ×107 ±0.1% B 5 M
Gray 8 ×108 ±0.05% A 1 K
White 9 ×109 – –
Gold – ×10-1 ±5% J –
Silver – ×10-2 ±10% K –
None – – ±20% M –
1. Any temperature coefficients not assigned its own letter shall be marked "Z", and the coefficient found in other documentation.
As an example, let us take a resistor which (read left to right) displays the colors yellow, violet, yellow, brown. We take the first two bands as the value, giving us 4, 7. Then the third band, another yellow, gives us the multiplier 104. Our total value is then 47 x 104 Ω, totalling 470,000 Ω or 470 kΩ. Our brown is then a tolerance of ±1%.
Resistors use specific values, which are determined by their tolerance. These values repeat for every order of magnitude; 6.8, 68, 680, and so forth. This is useful because the digits, and hence the first two or three stripes, will always be similar patterns of colors, which make them easier to understand.
Zero ohm resistors are manufactured; these are lengths of wire wrapped in a resistor-shaped body which can be substituted for another resistor value in automatic insertion equipment. They are marked with a single black band.
The 'body-end-dot' or 'body-tip-spot' system was used for radial-lead composition resistors sometimes found in vacuum-tube equipment; the first band was given by the body color, the second band by the color of the end of the resistor, and the multiplier by a dot or band around the middle of the resistor. The other end of the resistor was colored gold or silver to give the tolerance, otherwise it was 20%.
Extra bands on ceramic capacitors will identify the voltage rating class and temperature coefficient characteristics. A broad black band was applied to some tubular paper capacitors to indicate the end that had the outer electrode; this allowed this end to be connected to chassis ground to provide some shielding against hum and noise pickup.
Polyester film and "gum drop" tantalum electrolytic capacitors are also color coded to give the value, working voltage and tolerance.
Diode part number
The part number for diodes was sometimes also encoded as colored rings around the diode, using the same numerals as for other parts. The JEDEC "1N" prefix was assumed, and the balance of the part number was given by three or four rings.
Postage stamp capacitors and war standard coding
Capacitors of the rectangular 'postage stamp" form made for military use during World War II used American War Standard (AWS) or Joint Army Navy (JAN) coding in six dots stamped on the capacitor. An arrow on the top row of dots pointed to the right, indicating the reading order. From left to right the top dots were: black, indicating JAN mica or silver indicating AWS paper. first and second significant figures. The bottom three dots indicated temperature characteristic, tolerance, and decimal multiplier. The characteristic was black for +/- 1000 ppm/ degree c, brown for 500, red for 200, orange for 100, yellow for -20 to +1-- ppm/ degree c, and green for 0 to +70 ppm/degree C. A similar six-dot code by EIA had the top row as first, second and third significant digits and the bottom row as voltage rating (in hundreds of volts - no color indicated 500 volts), tolerance, and multiplier. A three-dot EIA code was used for 500 volt 20% tolerance capacitors, and the dots signified first and second significant digits and the multiplier. Such capacitors were common in vacuum tube equipment and in surplus for a generation after the war but are unavailable now.
Mnemonics
A useful mnemonic matches the first letter of the color code, by order of increasing magnitude. There are many variations:
· Badly Burnt Resistors On Your Ground Bus Void General Warranties
· Better Build Roof Over Your Garage Before Vehicle Gets Wet
· Boys better remember our young girls become very good wives.. BYU Engineering Department
· Bad boys rape our young girls behind victory garden walls.
· Bad boys rape 'onest young girls but virgins go without.
· Bad boys run our young girls behind victory garden walls.
· Bad boys rape our young girls but Violet gives willingly.
· Big boys race our young girls but Violet generally wins.
The tolerance codes, gold, silver, and none, are not usually included in the mnemonics; one extension that includes them is:
· Bad beer rots our young guts but vodka goes well – get some now.
Since B can stand for both "black" and "brown", variations are formed such as "Black boys rape our young girls...".
A politically-correct mnemonic that has attained some traction in recent years is:
· Big brown rabbits often yield great big vocal groans when gingerly slapped.
Another mnemonic that is not offensive and can be used in the classroom is:
· B. B. ROY of Great Britain has Very Good Wife.
Other mnemonics commonly taught in UK engineering courses include:
· Bye Bye Rosie Off You Go Birmingham Via Great Western
· Bye Bye Rosie Off You Go Bristol Via Great Western
· Bye Bye Rosie Off You Go But Via Great Western
· Bye Bye Rosie Off You Go do Become a Very Good Wife
· Bill Brown Realized Only Yesterday Good Boys Value Good Work
The colors are sorted in the order of the visible light spectrum: red (2), orange (3), yellow (4), green (5), blue (6), violet (7). Black (0) has no energy, brown (1) has a little more, white (9) has everything and grey (8) is like white, but less intense.
Examples
Resistors color code
From top to bottom:
· Green-Blue-Brown-Black-Brown
o 560 Ω ± 1%
· Red-Red-Orange-Gold
o 22,000 Ω ± 5%
· Yellow-Violet-Brown-Gold
o 470 Ω ± 5%
· Blue-Gray-Black-Silver
o 68 Ω ± 10%
Note: The physical size of a resistor is indicative of the power it can dissipate, not of its resistance.
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. The combination of components and wires allows various simple and complex operations to be performed: signals can be amplified, computations can be performed, and data can be moved from one place to another. Circuits can be constructed of discrete components connected by individual pieces of wire, but today it is much more common to create interconnections by photolithographic techniques on a laminated substrate (a printed circuit board or PCB) and solder the components to these interconnections to create a finished circuit. In an Integrated Circuit or IC, the components and interconnections are formed on the same substrate, typically a semiconductor such as silicon or (less commonly) gallium arsenide.
Breadboards, perfboards or stripboards are common for testing new designs. They allow the designer to make quick changes to the circuit during development.
An electronic circuit can usually be categorized as an analog circuit, a digital circuit or a mixed-signal circuit (a combination of analog circuits and digital circuits).
Analog circuits
Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented. Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits. In a series circuit, the same current passes through a series of components. A string of Christmas lights is a good example of a series circuit: if one goes out, they all do. In a parallel circuit, all the components are connected to the same voltage, and the current divides between the various components according to their resistance.
Digital circuits
In digital electronic circuits, electric signals take on discrete values, to represent logical and numeric values. These values represent the information that is being processed. In the vast majority of cases, binary encoding is used: one voltage (typically the more positive value) represents a binary '1' and another voltage (usually a value near the ground potential, 0 V) represents a binary '0'. Digital circuits make extensive use of transistors, interconnected to create logic gates that provide the functions of Boolean logic: AND, OR, NOT, and all possible combinations there of. Transistors interconnected so as to provide positive feedback are used as latches and flip flops, circuits that have two or more metastable states, and remain in one of these states until changed by an external input.
Digital circuits are fundamentally easier to design than analog circuits for the same level of complexity, because each logic gate regenerates the binary signal, so the designer need not account for distortion, gain control, offset voltages, and other concerns faced in an analog design. As a consequence, extremely complex digital circuits, with billions of logic elements integrated on a single silicon chip, can be fabricated at low cost. Such digital integrated circuits are ubiquitous in modern electronic devices, such as calculators, mobile phone handsets, and computers.
Mixed-signal circuits
Mixed-signal or hybrid circuits contain elements of both analog and digital circuits. Examples include comparators, timers, PLLs, ADCs (analog-to-digital converters), and DACs (digital-to-analog converters). Most modern radio and communications circuitry uses mixed signal circuits. For example, in a receiver, analog circuitry is used to amplify and frequency-convert signals so that they reach a suitable state to be converted into digital values, after which further signal processing can be performed in the digital domain.
References
Charles Alexander and Matthew Sadiku (2004). Fundamentals of Electric Circuits. McGraw-Hill.
John Hayes (1993). Introduction to Digital Logic Design. Addison Wesley.
Breadboards, perfboards or stripboards are common for testing new designs. They allow the designer to make quick changes to the circuit during development.
An electronic circuit can usually be categorized as an analog circuit, a digital circuit or a mixed-signal circuit (a combination of analog circuits and digital circuits).
Analog circuits
Analog electronic circuits are those in which current or voltage may vary continuously with time to correspond to the information being represented. Analog circuitry is constructed from two fundamental building blocks: series and parallel circuits. In a series circuit, the same current passes through a series of components. A string of Christmas lights is a good example of a series circuit: if one goes out, they all do. In a parallel circuit, all the components are connected to the same voltage, and the current divides between the various components according to their resistance.
Digital circuits
In digital electronic circuits, electric signals take on discrete values, to represent logical and numeric values. These values represent the information that is being processed. In the vast majority of cases, binary encoding is used: one voltage (typically the more positive value) represents a binary '1' and another voltage (usually a value near the ground potential, 0 V) represents a binary '0'. Digital circuits make extensive use of transistors, interconnected to create logic gates that provide the functions of Boolean logic: AND, OR, NOT, and all possible combinations there of. Transistors interconnected so as to provide positive feedback are used as latches and flip flops, circuits that have two or more metastable states, and remain in one of these states until changed by an external input.
Digital circuits are fundamentally easier to design than analog circuits for the same level of complexity, because each logic gate regenerates the binary signal, so the designer need not account for distortion, gain control, offset voltages, and other concerns faced in an analog design. As a consequence, extremely complex digital circuits, with billions of logic elements integrated on a single silicon chip, can be fabricated at low cost. Such digital integrated circuits are ubiquitous in modern electronic devices, such as calculators, mobile phone handsets, and computers.
Mixed-signal circuits
Mixed-signal or hybrid circuits contain elements of both analog and digital circuits. Examples include comparators, timers, PLLs, ADCs (analog-to-digital converters), and DACs (digital-to-analog converters). Most modern radio and communications circuitry uses mixed signal circuits. For example, in a receiver, analog circuitry is used to amplify and frequency-convert signals so that they reach a suitable state to be converted into digital values, after which further signal processing can be performed in the digital domain.
References
Charles Alexander and Matthew Sadiku (2004). Fundamentals of Electric Circuits. McGraw-Hill.
John Hayes (1993). Introduction to Digital Logic Design. Addison Wesley.
Digital Electronics
Digital electronics
Digital electronics represent signals by discrete bands of analog levels, rather than by a continuous range. All levels within a band represent the same signal state. Relatively small changes to the analog signal levels due to manufacturing tolerance, signal attenuation or parasitic noise do not leave the discrete envelope, and as result are ignored by signal state sensing circuitry.
In most cases the number of these states is two, and they are represented by two voltage bands: one near zero volts and a higher level near the supply voltage, corresponding to the "false" ("0") and "true" ("1") values of the boolean domain respectively.
Digital techniques are useful because it is easier to get an electronic device to switch into one of a number of known states than to accurately reproduce a continuous range of values.
Digital electronic circuits are usually made from large assemblies of logic gates, simple electronic representations of Boolean logic functions
Advantages
There are various advantages of digital signals over analog signals. Some of them are;
Signals represented digitally can be transmitted without degradation due to noise.
In a digital system, a more precise representation of a signal can be obtained by using more binary digits to represent it.
Information storage can be easier in digital systems than in analog ones.
Disadvantages
Digital circuits use more energy than analog circuits to accomplish the same tasks.
Digital circuits are sometimes more expensive, especially in small quantities.
Most useful digital systems must translate from continuous analog signals to discrete digital signals. This causes quantization errors.
References
Sedra and Smith, Microelectronic Circuits, Fourth Edition, Oxford University Press Inc, UK, [1998]
IEEE Dictionary of Electrical and Electronics Terms ISBN 978-0-471-42806-0
Null, Linda; Lobur, Julia (2006). The essentials of computer organization and architecture. Jones & Bartlett Publishers. p. 121. ISBN 0763737696.
Digital electronics represent signals by discrete bands of analog levels, rather than by a continuous range. All levels within a band represent the same signal state. Relatively small changes to the analog signal levels due to manufacturing tolerance, signal attenuation or parasitic noise do not leave the discrete envelope, and as result are ignored by signal state sensing circuitry.
In most cases the number of these states is two, and they are represented by two voltage bands: one near zero volts and a higher level near the supply voltage, corresponding to the "false" ("0") and "true" ("1") values of the boolean domain respectively.
Digital techniques are useful because it is easier to get an electronic device to switch into one of a number of known states than to accurately reproduce a continuous range of values.
Digital electronic circuits are usually made from large assemblies of logic gates, simple electronic representations of Boolean logic functions
Advantages
There are various advantages of digital signals over analog signals. Some of them are;
Signals represented digitally can be transmitted without degradation due to noise.
In a digital system, a more precise representation of a signal can be obtained by using more binary digits to represent it.
Information storage can be easier in digital systems than in analog ones.
Disadvantages
Digital circuits use more energy than analog circuits to accomplish the same tasks.
Digital circuits are sometimes more expensive, especially in small quantities.
Most useful digital systems must translate from continuous analog signals to discrete digital signals. This causes quantization errors.
References
Sedra and Smith, Microelectronic Circuits, Fourth Edition, Oxford University Press Inc, UK, [1998]
IEEE Dictionary of Electrical and Electronics Terms ISBN 978-0-471-42806-0
Null, Linda; Lobur, Julia (2006). The essentials of computer organization and architecture. Jones & Bartlett Publishers. p. 121. ISBN 0763737696.
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