positive feedback
91Greenhouse effect — The Greenhouse effect refers to the change in the thermal equilibrium temperature of a planet or moon by the presence of an atmosphere containing gas that absorbs infrared radiation. [ [http://www.ipcc.ch/pdf/assessment report/ar4/syr/ar4 syr… …
92Parasitic oscillation — is an undesirable oscillation caused by feedback. The problem occurs notably in RF [1], audio, and other electronic amplifiers[2] as well as in digital signal processing.[3] It is one of the fundamental issues addressed by control theory.[4] …
93Twelve leverage points — This article is about leverage points related to System Dynamics. For other uses, see Center of gravity (military). The twelve leverage points to intervene in a system were proposed by Donella Meadows, a scientist and system analyst focused on… …
94Neurofeedback — (NFB), also called neurotherapy, neurobiofeedback or EEG biofeedback is a type of biofeedback that uses realtime displays of electroencephalography or functional magnetic resonance imaging (fMRI) to illustrate brain activity, often with a goal of …
95drug — drug1 /drug/, n., v., drugged, drugging. n. 1. Pharm. a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well being. 2. (in federal law) a. any substance… …
96Drug — /droog/, n. Zoroastrianism. the cosmic principle of disorder and falsehood. Cf. Asha. [ < Avestan drauga] * * * I Any chemical agent that affects the function of living things. Some, including antibiotics, stimulants, tranquilizers,… …
97Virtual ground — In the theory of electrical networks, a virtual ground ( or virtual earth) is a node of the circuit that is maintained at a steady reference potential, without being connected directly to the reference potential. In some cases the reference… …
98Snowball Earth — The Snowball Earth hypothesis as it was originally proposedcite book author = Kirschvink, J.L. year = 1992 chapter = Late Proterozoic low latitude global glaciation: The snowball Earth title = The Proterozoic Biosphere: A Multidisciplinary Study… …
99Effects of global warming — This article is about (primarily) effects during the 21st century. For longer term effects, see Long term effects of global warming. The variou …
100Bipolar transistor biasing — Bipolar transistor amplifiers must be properly biased to operate correctly. In circuits made with individual devices (discrete circuits), biasing networks consisting of resistors are commonly employed. Much more elaborate biasing arrangements are …
