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Pulse-width Modulation
Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a method of reducing the average power delivered by an electrical signal, by effectively chopping it up into discrete parts. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The longer the switch is on compared to the off periods, the higher the total power supplied to the load. Along with maximum power point tracking (MPPT), it is one of the primary methods of reducing the output of solar panels to that which can be utilized by a battery. PWM is particularly suited for running inertial loads such as motors, which are not as easily affected by this discrete switching, because their inertia causes them to react slowly. The PWM switching frequency has to be high enough not to affect the load, which is to say that the resultant waveform perceived by the load must be as smooth as possible. The rate (or frequency) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheostat
A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load. Nomenclature There are a number of terms in the electronics industry used to describe certain types of potentiometers: * slide pot or slider pot: a potentiomete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangle Wave
A triangular wave or triangle wave is a non-sinusoidal waveform named for its triangular shape. It is a periodic, piecewise linear, continuous real function. Like a square wave, the triangle wave contains only odd harmonics. However, the higher harmonics roll off much faster than in a square wave (proportional to the inverse square of the harmonic number as opposed to just the inverse). Definitions Definition A triangle wave of period ''p'' that spans the range ,1is defined as: x(t)= 2 \left, \frac - \left \lfloor \frac + \frac \right \rfloor \ where \lfloor\,\ \rfloor is the floor function. This can be seen to be the absolute value of a shifted sawtooth wave. For a triangle wave spanning the range the expression becomes: x(t)= 2 \left , 2 \left ( \frac - \left \lfloor + \right \rfloor \right) \right , - 1. A more general equation for a triangle wave with amplitude a and period p using the modulo operation and absolute value is: y(x) = \frac \left, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sawtooth Wave
The sawtooth wave (or saw wave) is a kind of non-sinusoidal waveform. It is so named based on its resemblance to the teeth of a plain-toothed saw with a zero rake angle. A single sawtooth, or an intermittently triggered sawtooth, is called a ramp waveform. The convention is that a sawtooth wave ramps upward and then sharply drops. In a reverse (or inverse) sawtooth wave, the wave ramps downward and then sharply rises. It can also be considered the extreme case of an asymmetric triangle wave. The equivalent piecewise linear functions x(t) = t - \lfloor t \rfloor x(t) = t \bmod 1 based on the floor function of time ''t'' is an example of a sawtooth wave with period 1. A more general form, in the range −1 to 1, and with period ''p'', is 2\left( - \left\lfloor + \right\rfloor\right) This sawtooth function has the same phase as the sine function. While a square wave is constructed from only odd harmonics, a sawtooth wave's sound is harsh and clear and its spectru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Average
In ordinary language, an average is a single number taken as representative of a list of numbers, usually the sum of the numbers divided by how many numbers are in the list (the arithmetic mean). For example, the average of the numbers 2, 3, 4, 7, and 9 (summing to 25) is 5. Depending on the context, an average might be another statistic such as the median, or mode. For example, the average personal income is often given as the median—the number below which are 50% of personal incomes and above which are 50% of personal incomes—because the mean would be higher by including personal incomes from a few billionaires. For this reason, it is recommended to avoid using the word "average" when discussing measures of central tendency. General properties If all numbers in a list are the same number, then their average is also equal to this number. This property is shared by each of the many types of average. Another universal property is monotonicity: if two lists of numbers ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rectangular Wave
A pulse wave or pulse train is a type of non-sinusoidal waveform that includes square waves (duty cycle of 50%) and similarly periodic but asymmetrical waves (duty cycles other than 50%). It is a term used in synthesizer programming, and is a typical waveform available on many synthesizers. The exact shape of the wave is determined by the duty cycle or pulse width of the oscillator output. In many synthesizers, the duty cycle can be modulated ( pulse-width modulation) for a more dynamic timbre.Reid, Gordon (February 2000). Synth Secrets: Modulation, ''SoundOnSound.com''. Retrieved May 4, 2018. The pulse wave is also known as the rectangular wave, the periodic version of the rectangular function. The average level of a rectangular wave is also given by the duty cycle, therefore by varying the on and off periods and then averaging these said periods, it is possible to represent any value between the two limiting levels. This is the basis of pulse-width modulation. Frequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duty Cycle General
A duty (from "due" meaning "that which is owing"; fro, deu, did, past participle of ''devoir''; la, debere, debitum, whence "debt") is a commitment or expectation to perform some action in general or if certain circumstances arise. A duty may arise from a system of ethics or morality, especially in an honor culture. Many duties are created by law, sometimes including a codified punishment or liability for non-performance. Performing one's duty may require some sacrifice of self-interest. Cicero, an early Roman philosopher who discusses duty in his work “On Duty", suggests that duties can come from four different sources: # as a result of being a human # as a result of one's particular place in life (one's family, one's country, one's job) # as a result of one's character # as a result of one's own moral expectations for oneself The specific duties imposed by law or culture vary considerably, depending on jurisdiction, religion, and social normalities. Civic duty Duty is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ward Leonard Control
Ward Leonard control, also known as the Ward Leonard drive system, was a widely used DC motor speed control system introduced by Harry Ward Leonard in 1891. In the early 1900s, the control system of Ward Leonard was adopted by the U.S. Navy and also used in passenger lifts of large mines. It also provided a solution to a moving sidewalk at the Paris Exposition of 1900, where many others had failed to operate properly. It was applied to railway locomotives used in World War I, and was used in anti-aircraft radars in World War II. Connected to automatic anti-aircraft gun directors, the tracking motion in two dimensions had to be extremely smooth and precise. The MIT Radiation Laboratory selected Ward-Leonard to equip the famous radar SCR-584 in 1942. The Ward Leonard control system was widely used for elevators until thyristor drives became available in the 1980s, because it offered smooth speed control and consistent torque. Many Ward Leonard control systems and variations on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinclair Radionics
Sinclair Radionics Ltd was a company founded by Sir Clive Sinclair in Cambridge, England which developed hi-fi products, radios, calculators and scientific instruments. History After raising funds to start the business by writing articles for ''Practical Wireless'' magazine, and borrowing £50, Clive Sinclair founded Sinclair Radionics Ltd. on 25 July 1961. Sinclair initially worked alone in the evenings in a room in London (he was still a technical journalist during the day), selling radio kits by mail order. Radios and Hi-Fi Radionics initially developed hi-fi equipment; it released its first product, the Sinclair Micro-amplifier, in December 1962. The assembly and distribution of this product were contracted out to Cambridge Consultants. In 1963 Sinclair Radionics introduced their first radio with the "Sinclair Slimline" in kit form at forty-nine shillings and sixpence (£2.47½). A year later, in 1964, Sinclair released the "X-10" amplifier, one of the first comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soundtrack
A soundtrack is recorded music accompanying and synchronised to the images of a motion picture, drama, book, television program, radio program, or video game; a commercially released soundtrack album of music as featured in the soundtrack of a film, video, or television presentation; or the physical area of a film that contains the synchronised recorded sound. In movie industry terminology usage, a sound track is an audio recording created or used in film production or post-production. Initially, the dialogue, sound effects, and music in a film each has its own separate track (''dialogue track'', ''sound effects track'', and '' music track''), and these are mixed together to make what is called the ''composite track,'' which is heard in the film. A ''dubbing track'' is often later created when films are dubbed into another language. This is also known as an M&E (music and effects) track. M&E tracks contain all sound elements minus dialogue, which is then supplied by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Sound
Optical sound is a means of storing sound recordings on transparent film. Originally developed for military purposes, the technology first saw widespread use in the 1920s as a sound-on-film format for motion pictures. Optical sound eventually superseded all other sound film technologies until the advent of digital sound became the standard in cinema projection booths. Optical sound has also been used for multitrack recording and for creating effects in some musical synthesizers. 1914-1921: Naval and military use Building on the principle first demonstrated by the Photophone of Alexander Graham Bell in 1880, optical sound was developed by several inventors with an interest in wireless communication through transmission of light, primarily for ship-to-ship use. The idea was that sound pulses could be converted into light pulses, beamed out from one ship and picked up by another, where the light pulses would then be reconverted into sound. A pioneer in this technology was Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philips
Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters is still in Eindhoven. Philips was formerly one of the largest electronics companies in the world, but is currently focused on the area of health technology, having divested its other divisions. The company was founded in 1891 by Gerard Philips and his father Frederik, with their first products being light bulbs. It currently employs around 80,000 people across 100 countries. The company gained its royal honorary title (hence the ''Koninklijke'') in 1998 and dropped the "Electronics" in its name in 2013, due to its refocusing from consumer electronics to healthcare technology. Philips is organized into three main divisions: Personal Health (formerly Philips Consumer Electronics and Philips Domestic Appliances and Personal Care), Connecte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
