A layman's journey to the frontiers of physics.
Alternator. In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines.
An alternator that uses a permanent magnet for its magnetic field is called a magneto. Alternators in power stations driven by steam turbines are called turbo-alternators. History[edit] Alternating current generating systems were known in simple forms from the discovery of the magnetic induction of electric current in the 1830s. The early machines were developed by pioneers such as Michael Faraday and Hippolyte Pixii.
Bipolar junction transistor. Schematic symbols for PNP- and NPN-type BJTs.
A bipolar junction transistor (BJT or bipolar transistor) is a type of transistor that relies on the contact of two types of semiconductor for its operation. BJTs can be used as amplifiers, switches, or in oscillators. BJTs can be found either as individual discrete components, or in large numbers as parts of integrated circuits. Charge flow in a BJT is due to diffusion of charge carriers across a junction between two regions of different charge concentrations. Speed of Light as calculated in Ancient India.