A classic application for a pair of class-A devices is the long-tailed pair, which is exceptionally linear, and forms the basis of many more complex circuits, including many audio amplifiers and almost all op-amps.

Its input stage used a long-tailed triode pair with loads matched to reduce drift in the output and, far more importantly, it was the first op-amp design to have two inputs ( one inverting, the other non-inverting ).

A common circuit using this last technique is the long-tailed pair, often seen in television sets and oscilloscopes.

The long-tailed pair was originally implemented using a pair of vacuum tubes.

The long-tailed pair was developed from earlier knowledge of push-pull circuit techniques and measurement bridges.

The earliest circuit that is truly recognizable as a long-tailed pair in its conventional form is given by Matthews ( 1934 ) and the same circuit form appears in a patent submitted by Alan Blumlein in 1936.

The long-tailed pair was very successfully used in early British computing, most notably the Pilot ACE Model and descendants, Wilkes ' EDSAC, and probably others designed by people who worked with Blumlein or his peers.

A differential ( long-tailed, emitter-coupled ) pair amplifier consists of two amplifying stages with common ( emitter, source or cathode ) degeneration.

Figure 2: A classic long-tailed pair

Figure 3: An improved long-tailed pair with current mirror | current-mirror load and constant-current biasing

In discrete electronics, a common arrangement for implementing a differential amplifier is the long-tailed pair, which is also usually found as the differential element in most op-amp integrated circuits.

A long-tailed pair can be used as an analog multiplier with the differential voltage as one input and the biasing current as another.

The Philippine Eagle was known initially as the Philippine Monkey-Eating Eagle because it was believed to feed on monkeys ( the only monkey native to the Philippines is the Philippine long-tailed macaque ) almost exclusively ; this has proven to be inaccurate.

The long-tailed planigale has an extraordinary head shape.

The long-tailed weasel has well-developed anal scent glands, which produce a strong and musky odour.

A broad-winged and long-tailed, it also has long legs and frequently walks and runs on the ground.

The juvenile is streaked and has a spotted mantle. It is an upright long-tailed flycatcher.

Despite its bulky, long-tailed appearance, this pigeon has a fast, direct flight.

Despite its bulky, long-tailed appearance, this pigeon has a fast, direct flight.

The Wrentit has been variously placed in its own family, the Chamaeidae, or with the long-tailed tits ( Aegithalidae ), the true tits and chickadees ( Paridae ), the " Old World warblers " ( Sylviidae ), and with the " Old World babblers " ( Timaliidae ).

Until now the false gharial was thought to have a diet similar to its relative the true gharial, i. e. only fish and very small vertebrates, but new evidence and occurrences have proven that the false gharial's broader snout has enabled larger individuals to prey on larger vertebrates including Proboscis monkeys, long-tailed macaques, deer and fruit bats.

In Tuva, Campbell's dwarf hamster has been found living with other hamsters such as the Chinese striped hamster, the roborovski hamster and the long-tailed dwarf hamster.

The female widow bird will desire to mate with the most attractive long-tailed male so that her progeny, if male, will themselves be attractive to females of the next generation-thereby fathering many offspring who will carry the female's genes.

But many species of moderate altitudes — for example the long-tailed pheasants of the genus Syrmaticus — also find a great deal of their daily nutritional reqirements in the tree canopies, especially during the snowy and rainy periods when foraging on the ground is dangerous and less than fruitful for a variety of reasons.

There are large hatches of mayflies, whose long-tailed, short-lived adults are a favourite food of trout ; many species of water beetle and insect larvae.

Presumably, individuals had been sighted many times during the years when it was " extinct ", but mistaken for an especially slender and long-tailed example of the otherwise similar red-legged or red-necked pademelon.

This may be because there are no long-tailed and pig-tailed macaques ( the reservoir hosts of P. knowlesi ) in Africa and many West Africans lack the Duffy antigen-a protein on the surface of the red blood cell that the parasite to uses to invade.

Birds are represented by Barnacle Goose, pink-footed goose, snow goose, whooper swan, King Eider, Common Eider, long-tailed duck, Brunnich's guillemot, black guillemot, little auk, puffin, fulmar, herring gull, glaucous gull, Great Black-backed Gull, kittiwake, Arctic tern, red-throated diver, great Northern Diver, red-breasted merganser, ptarmigan, raven, snowy owl, Greenlandic gyrfalcon, etc.

Whimbrel, long-tailed jaeger, eagle and rough-legged buzzard can also be seen and with a bit of luck the unusual species lesser white-fronted goose, gyrfalcon and great grey owl can be observed.

Given the diminishing cost of communication and information sharing ( by analogy to the low cost of storage and distribution, in the case of e-tailers ), long-tailed user driven innovation will gain importance for businesses.

The stoat and the long-tailed weasel remained separated until half a million years ago, when falling sea levels exposed the Bering land bridge.

The long-tailed weasel is the product of a process begun 5 – 7 million years ago, when northern forests were replaced by open grassland, thus prompting an explosive evolution of small, burrowing rodents.

The long-tailed weasel and the stoat remained separated until half a million years ago, when falling sea levels exposed the Bering land bridge, thus allowing the stoat to cross into North America.

They are often very conspicuous, particularly when the long-tailed males are incubating.

Placement in a superfamily Sylvioidea which contained birds such as Sylviidae, Timaliidae and long-tailed tits-but not Paridae-was confirmed.

In the early 1960s, 680 long-tailed males were examined that are contained in collections of the British Museum of Natural History, Chicago Natural History Museum, Peabody Museum, Carnegie Museum, American Museum of Natural History, United States National Museum and Royal Ontario Museum.

In more primitive, long-tailed pterosaurs (" rhamphorhynchoids ") such as Rhamphorhynchus, the average growth rate during the first year of life was 130 % to 173 %, slightly faster than the growth rate of alligators.

An equivalent way of expressing this is that if most females are looking, for example, for long-tailed males, then each female individually does better to select a long-tailed male, since then her male children are more likely to succeed.

Thus, at a given temperature, a short-tailed lipid will be more fluid than an otherwise identical long-tailed lipid.

In general appearance as well as habits they resemble large long-tailed sunbirds, but are possibly more closely related to the Australian honeyeaters.

Barosaurus ; Greek barys / βαρυς meaning ' heavy ' and saurus / σαυρος meaning ' lizard ', ' heavy lizard ') was a giant, long-tailed, long-necked, plant-eating dinosaur closely related to the more familiar Diplodocus.

What is unusual about a long-tailed distribution is that the most frequently occurring 20 % of items represent less than 50 % of occurrences ; or in other words, the least frequently occurring 80 % of items are more important as a proportion of the total population.

Sexual dimorphism can be pronounced ( and of course more so in the long-tailed males ) or subtle ; the female Bedford's Paradise Flycatcher is identical to the male except slightly duller.