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.

The long-tailed pair has many attributes as a switch: largely immune to tube ( transistor ) variations ( of great importance when machines contained 1, 000 or more tubes ), high gain, gain stability, high input impedance, medium / low output impedance, good clipper ( with not-too-long tail ), non-inverting ( EDSAC contained no inverters!

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.

The Common Buzzard can be similar-looking, with a similar long-tailed shape and can be notoriously variable in plumage.

The long-tailed weasel's growth rate is rapid, as by the age of three weeks, the kits are well furred, can crawl outside the nest and eat meat.

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.

One of only two living species of bat in New Zealand, they can be easily distinguished from New Zealand long-tailed bats by the presence of relatively large, pointed ears, prominent nostrils, and by their tail.

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.

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.

Many of the smaller, long-tailed species of lories may be referred to as lorikeets.

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.

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

In the Sibley-Ahlquist taxonomy, the Paridae family is much enlarged to include related groups such as the Penduline tits and Long-tailed tits, but while the former are quite close to the titmice indeed and could conceivably be included in that family together with the stenostirid " warblers ", the long-tailed tits are not.

The long-tailed weasel is an obligate carnivore which prefers its prey to be fresh or alive, eating only the carrion stored within its burrows.

The shiny long-tailed males of this species get to be up to 70 cm in body length, while the smaller and less showy females measure up to 47 cm.

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.

The word " quetzal " was originally used for just the Resplendent Quetzal, the famous long-tailed quetzal of Central America, which is the national bird and the name of the currency of Guatemala.

Some paleobiologists report that, based on computer models of their biomechanical capabilities, certain long-tailed dinosaurs such as Apatosaurus and Diplodocus may have possessed the ability to flick their tails at supersonic velocities, possibly used to generate an intimidating booming sound.

In February 2012 Colmans ', the company whose mustard is used by the club for its initiation rites, launched a TV advert in the UK featuring a comic minotaur character who is dressed in the Bullingdon Club uniform of teal blue long-tailed frock coat and mustard yellow waistcoat ; and whose voice, mannerisms and blonde haircut all parody those of former club member and London Mayor Boris Johnson.

In Bangkok, the Chao Phraya River is a major transportation artery, with ferries, water taxis ( the Chao Phraya Express ) and long-tailed boats.

A red lacquerware food tray with gold foil engraving designs of two long-tailed birds and a peony, dated 12th to early 13th century.

Mammals which call these places home include the red fox, long-tailed weasel, mink, muskrat, woodchuck, several bat species, bottlenose dolphins, harbour porpoises and possibly river otters which are close to local extinction in Long Island with only an estimated 8 individuals thought to have recently migrated from Connecticut.

The Nightjar flies at dusk, most often at sundown, a long-tailed, shadowy form with easy, silent moth-like flight ; its strong and deliberate wingbeats alternate with graceful sweeps and wheels with motionless wings.

It is the largest subspecies, long-tailed, and with blue or purple-blue glossed feathers.

The head shape aside ( which in any case is not obvious from all angles ), the long-tailed planigale looks rather like a very small mouse with a long, bare tail.

The long-tailed planigale prefers floodplains and savannah woodlands with cracked clay soils, as well as riparian areas and blacksoil plains.

The long-tailed Gentoo penguin ( ), Pygoscelis papua, is a penguin species in the genus Pygoscelis, most closely associated with the Adélie penguin ( P. adeliae ) and the Chinstrap penguin ( P. antarcticus ).

The original character 猓, with the " dog radical " 犭and a guǒ 果 phonetic, was considered condescending, comparable to the Chinese name guǒran 猓然 " a long-tailed ape ".

The Dark Chanting Goshawk is a large, long-tailed, broad-winged hawk, with a 105 cm wingspan.

alt = a small long-tailed vivid pale blue and black bird standing on the ground facing the camera, with its cheek feathers puffed out

The long-tailed weasel is one of the largest members of the genus Mustela in North America, with a total length of 300 – 350 mm and a tail comprising 40 – 70 % of the head and body length.

In northern areas in winter, the long-tailed weasel's fur becomes white, sometimes with yellow tints, but the tail retains its black tip.

The long-tailed weasel mates in July – August, with implantation of the fertilized egg on the uterine wall being delayed until about March.