Amplifier

See also: electronic amplifier, low noise amplifier, preamplifier, satellite in-line amplifier. The plant marketed as "lucky bamboo" is actually an entirely unrelated species, Dracaena sanderiana. Optical amplifiers amplify light, through the process of stimulated emission. Soft bamboo shoots, stems, and leaves are the major food source of the Giant Panda of China and the Spider monkey. An Amplidyne or Rototrol is a rotating machine like an electrical generator that provides amplification of electrical signals by conversion of mechanical energy to electrical energy. The four plants are commonly mentioned together as "mei2 lan2 zhu2 ju2" (梅蘭竹菊). The bandwidth of magnetic amplifiers extends to the tens of kilohertz. Each plant represents a particular aspect of a noble person in Confucian ideology.

It is a non-electronic electrical amplifier with no moving parts. In Chinese culture, the bamboo (竹), along with mei (梅, the same tree as Japanese ume), orchids (蘭), and chrysanthemum (菊) are all held in high esteem and are collectively referred as the "the four of great nobility" (四君子). A magnetic amplifier is a transformer-like device that makes use of the saturation of magnetic materials to produce amplification. Hawaiian bamboo ('ohe) is a kinolau or body form of the Polynesian creator god Kane. The carbon microphone was extremely important in early telecommunications until other types of amplifiers were available. Also, bamboo is considered second in the rank in the order of "Matsu (pine wood), Take (bamboo), Ume (sometimes translated as apricot or plum)" and this order is used when ordering a sushi course or getting a room in a traditional Ryokan inn. By channeling a large electric current through the compressed carbon granules in the microphone, a small sound signal could produce a much larger electric signal. In Japan, a bamboo forest sometimes surrounds a Shinto shrine as part of a sacred barrier against evils.

One of the first devices to amplify signals was the carbon microphone. In the Philippines, bamboo crosses are used as a good luck charm by farmers. An audio amplifier is usually used to amplify signals such as music or speech. Malaysian legends include the story of a man who dreams of a beautiful woman while sleeping under a bamboo plant; he wakes up and breaks the bamboo stem, discovering the woman inside. See main page: instrument amplifier. Several Asian cultures, including that of the Andaman Islands, believe that humanity emerged from a bamboo stem. An operational amplifier is a solid state integrated circuit amplifier which employs external feedback for control of its transfer function or gain. Its rare blossoming has led to the flowers' being regarded as a sign of impending famine.

The amount of magnification (the "forward gain") is determined by the external circuit design as well as the active device. Bamboo's long life makes it a Chinese symbol of long life, while in India it is a symbol of friendship. The essential role of this active element is to magnify an input signal to yield a significantly larger output signal. A variety of bamboo was one of about two dozen plants carried by Polynesian voyagers to provide all their needs settling new islands; in the Hawaiian Islands, among many uses, 'Ohe (bamboo) carried water, made irrigation troughs for taro terraces, was used as a traditional knife for cutting the umbilical cord of a newborn, as a stamp for dyeing bark tapa cloth, and for four hula instruments - nose flute, rattle, stamping pipes and Jews harp. Most common active devices in transistor amplifiers are bipolar junction transistors (BJTs); metal oxide semiconductor field-effect transistors (MOSFETs) are also used. The wood is used for knitting needles and the fibre can be used for yarn. In the earlier years of audio, vacuum tubes filled the active device role. Coarse bamboo paper is still used to make spirit money in many Chinese communities.

Some claim this sound has more to do with the circuit topology and circuit design of the amplifier, than to the use of valves rather than transistors as the active gain devices. A high quality hand-made paper is still produced in small quantities. Valve amplifiers are widely, but not always correctly, associated with the valve sound. The fibre of bamboo has been used to make paper in China since early times. Today most sound systems use transistor amplifiers for economic reasons, but valve amplifiers remain popular for guitar amplification, for "high end" hi-fi systems and analog production and replay equipment in recording studios. Every few days the tube is removed and replaced higher up the fast-growing culm. The signal is restored to almost sinusoidal shape by the tuned circuit. Bamboo canes are normally round in cross-section, but square canes can be produced by forcing the new young culms to grow through a tube of square cross-section and slightly smaller than the culm's natural diameter, thereby constricting the growth to the shape of the tube.

RF tuned amplifiers are usually Class C which means that they amplify less than 180° of the input signal. Culms may be cut and hollowed into vases or drinkware, tubes, or pipes for liquids. These classes are usually used in efficient low frequency amplifiers (such as audio and hi-fi) owing to their relatively high efficiency. When bamboo is harvested for wood, care is needed to select mature stems that are several years old, as first-year stems, although full size, are not fully woody and are not strong. Class AB and class B are essentially the same, transmitting about 180deg of the input signal to the output with each device. However bamboo wood is easily infested by wood-boring insects unless treated with wood preservatives or kept very dry. Where efficiency is not a consideration, most small signal linear amplifiers are designed as class A which means that one active device amplifies all portions (360deg) of the input signal. Modern companies are attempting to popularize flooring made of bamboo pieces steamed, flattened, glued together, finished, and cut.

All amplifiers can be classified by the angle of flow of the input signal through the amplifying device; see electronic amplifier. This makes it useful for many things such as houses (in tropical climates), fences, bridges, walking sticks, furniture, chopsticks, food steamers, toys, construction scaffolding, hats, abaci and various musical instruments such as the shakuhachi, and jinghu. Its critical components are active devices, such as vacuum tubes or transistors. Bamboo forms a very hard wood, especially when seasoned, and is light and exceptionally tough. The most common type of amplifier is the electronic amplifier, commonly used in radio and television transmitters and receivers, high-fidelity ("hi-fi") stereo equipment, microcomputers and other electronic digital equipment, and guitar and other instrument amplifiers. Zhúyèqīng jiǔ (竹叶青酒) is a green-colored Chinese liquor that has bamboo leaves as one of its ingredients. There are numerous types of electronic amplifier depending upon the application. The sap of young stalks tapped during the rainy season may be fermented to make ulanzi (a sweet wine), or simply made into a soft drink.

Note that more efficient amps run much cooler, and often do not need any fans even in multi-kilowatt designs. Pickled bamboo, used as a condiment, may also be made from the pith of the young shoots. The efficiency of the amplifier limits the amount of total power output that is usefully available. However, the shoots of some species contain toxins that need to be leached or boiled out before they can be eaten safely. Commercially available class D amplifiers have reported efficiencies as high as 97%. They are used in Asian stir fry, and are available in supermarkets in various sliced forms. Modern Class AB amps are commonly between 35–55% efficient with a theoretical maximum of 78.5%. The shoots (new bamboo culms that come out of the ground) of bamboo, called zhú sǔn (竹笋) in Chinese, are edible.

How much of the input power is usefully applied to the amplifier's output? Class A amplifiers are very inefficient, in the range of 10–20% with a max efficiency of 25%. A newly transplanted bamboo plant can take 1-2 years before it sends up new shoots (culms) and will have many seasons of "sizing up" before new shoots achieve the maximum potential height for that species. It is measured in either decibels or the peak output voltage produced by the amp when no signal is applied. For the species most widely cultivated in gardens, 3-5 cm per day is more typical. How much noise is introduced by the amplification process? This is an undesirable thing that is the inevitable result of the electronics devices and components. Several subtropical bamboo species can grow 30 cm (1 foot) per day, with some species having been documented as growing over 100 cm in one day. The total harmonic distortion (THD) is the sum of these components relative to the signal. Established bamboo will send up shoots that generally grow to their full height in a single season, making it the fastest growing woody plant.

These are the harmonics. Since the new roots are dependent on older parts of the root system for nourishment, anything beyond the shovel cut will die in the ground and be unable to reestablish itself. You will sometimes see humps at even intervals along the graph at even multiples of that base signal. The root system is generally very close to the surface, so, if rhizome pruning is done twice a year, it will sever most, if not all, of the new growth. The largest signal on your analyzer should be the input signal at 1 kHz. The second method is rhizome pruning, which involves taking a sharp spade and cutting down into the ground 30 cm (1 foot) all along the perimeter that is to be maintained. Typically a sinusoidal signal of 1 kHz is used. The first involves surrounding it with a physical barrier, usually a special, high density, plastic roll material made for this purpose; this is placed in a 60-90 cm (2-3 feet) deep ditch around the planting, and angled out at the top to direct the rhizomes to the surface.

Then a pure tone is applied to the amplifier input. There are two main ways to prevent the spread of running bamboo into adjacent areas. The amplifier output is connected to a spectrum analyzer, (a device which graphs frequency against amplitude). The reputation of bamboo as being highly invasive is often exaggerated, and situations where it has taken over large areas is often the result of years of untended or neglected plantings. Harmonic distortion is fairly easy to measure. If bamboo must be removed, an alternative to digging it up is to cut down the culms, and then repeatedly mow down new shoots as they arise, until the root system exhausts its energy supply and dies. This distortion comes in several forms including harmonic distortion and intermodulation distortion. Once established as a grove, it is difficult to completely remove bamboo without digging up the entire network of underground rhizomes.

The properties of amplifier circuits distort the signal. If neglected, they can be invasive over time and can cause problems by moving into adjacent areas. This is the maximum rate of change of output variable, usually quotes in volts per second (or microsecond). Some can send out runners several metres a year, while others can stay in the same general area for long periods. Specified in high accuracy measurement systems. Running bamboo species are highly variable in their tendency to spread; this is related to both the species and the soil and climate conditions. Time taken for output to settle to within a certain percentage of the final value say 0.1%. Clumping bamboo species tend to spread underground slowly.

where BW is in Hz and Tr is in seconds. There are two patterns for the spreading of bamboo, "clumping" (monopodial) and "running" (sympodial). Tr = BW/0.35. They spread mainly through their roots and/or rhizomes, which can spread widely underground and send off new culms to break through the surface. For a Gaussian response system (or a simple RC roll off), the rise time is given by :. In cultivation, care needs to be taken of their potential for invasive behaviour. The rise time of an amplifier is the time taken for the out put to change from 10% to 90% of its final level when driven by a step input. Many bamboos are popular in cultivation as garden plants.

As an example, a good audio amplifier will have a −3 dB BW from around twenty hertz to about twenty kilohertz (the range of normal human hearing). This is thought to have evolved to reduce the effect of predators of the seed, who would be unable to depend on a predictable food supply. Bandwidths for other response tolerances are sometimes quoted (−1 dB, −6 dB etc. Furthermore, all the individuals of the species will flower at the same time in a large geographical region. This is therefore also known as the −3 dB BW. Some of these species are monocarpic, the plant dying after the seed matures. The bandwidth BW of an amplifier is usually defined as the difference between the lower and upper half power points. Some species of bamboo rarely flower, some of them only every 10-100 or more years.

Since the lowest useful level is limited by output noise, this is quoted as the amplifier dynamic range. A single stem of bamboo from an established root system typically reaches full height in just one year, but then persists for several years, gradually increasing the number of side branches and branchlets. This is the range usually quoted in dB between the lowest useful; output and the largest useful output level. For comparison, palms, which like bamboos are monocotyledons, are equally dissimilar to other trees, yet are usually called trees. Mathematically speaking, the gain is equal to the output level divided by the input level. Many of the larger bamboos are very tree-like in appearance, but perhaps illogically they are rarely called trees, despite that term being a growth form, not a botanical term. This is usually measured in decibels (dB). They are thus, unlike most other grasses, extensively branched; in large-growing species a single stem may carry many thousands of branchlets.

How much an amplifier increases the signal level is called the gain. The stems are jointed, with regular nodes; each node bears one leaf, and may also have one to several side branches. Most amplifiers can be characterised by a number of parameters. The stems, or 'culms', can range in height from a few centimetres to 40 metres, with stem diameters ranging from 1 mm to 30 cm. . . The relationship of the input to the output of an amplifier — usually expressed as a function of the input frequency — is called the transfer function of the amplifier, and the magnitude of the transfer function is termed the gain. Major areas with no native bamboos include Europe, North Africa, Western Asia, northern North America, most of Australia and Antarctica.

An amplifier can be considered to be any device that uses a small amount of energy to control a larger amount, although the term today usually refers to an electronic amplifier. They also occur in sub-Saharan Africa, and in the Americas from the southeast of the USA south to Chile, there reaching their furthest south anywhere, at 47°S latitude. Another type of amplifier is the fluidic amplifier, based on the fluidic triode. They occur from Northeast Asia (at 50°N latitude in Sakhalin), south throughout East Asia west to the Himalaya, and south to northern Australia. Relays can be included under the above definition of amplifiers, although their transfer function is not linear (that is, they are either open or closed). Bamboos are found in diverse climates, from cold mountains to hot tropical regions. There are also mechanical amplifiers, such as the automotive servo used in braking. Some of its members are giants, forming by far the largest members of the grass family.

Bamboos are a group of woody perennial evergreen plants in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Shibataeinae. Racemobambodinae. Nastinae.

Melocanninae. Guaduinae. Chusqueinae. Bambusinae.

Arundinariinae. Arthrostylidiinae.