Small Signal Approximation
Nonlinear elements such as transistors tend to behave linearly when small AC signals are applied to them. So in analysing many circuits where the signal levels are small, for example those in TV and radio receivers, nonlinear elements can be replaced with a linear small-signal model, allowing linear analysis techniques to be used.
Conversely, many linear circuit elements show nonlinearity as the signal level is increased. If nothing else, the power supply voltage to the circuit usually puts a limit on the magnitude of voltage output from a circuit. Above that limit, the output ceases to scale in magnitude with the input, failing the definition of linearity.
Read more about this topic: Linear Circuit
Famous quotes containing the words small and/or signal:
“If you tie a horse to a stake, do you expect he will grow fat? If you pen an Indian up on a small spot of earth, and compel him to stay there, he will not be contented, nor will he grow and prosper. I have asked some of the great white chiefs where they get their authority to say to the Indian that he shall stay in one place, while he sees white men going where they please. They can not tell me.”
—Chief Joseph (c. 1840–1904)
“Certainly the effort to remain unchanged, young, when the body gives so impressive a signal of change as the menopause, is gallant; but it is a stupid, self-sacrificial gallantry, better befitting a boy of twenty than a woman of forty-five or fifty. Let the athletes die young and laurel-crowned. Let the soldiers earn the Purple Hearts. Let women die old, white-crowned, with human hearts.”
—Ursula K. Le Guin (b. 1929)