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--- glossary:glossary_a [2019/09/05 20:30] – [Amplifier] more complete and useful answer tgerbic
+++ glossary:glossary_a [2019/09/09 08:25] – [AC] Expanded with more useful information. tgerbic
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-Alternating Current - Generally with a sinusoidal wave form. Mains power in Britain and Europe is 230v AC at 50Hz, that is 50 complete cycles per second. USA uses 115v at 60Hz.\\
+Alternating Current. Refers to a situation where current flows back and forth through a conductor (wire) in alternating directions. Generally, the voltage being applied to the conductor has a changing (alternating) polarity so the current has to change direction related to which end of the wire is positive or negative at a given point of time. In most cases we encounter, the voltage moves in a sinusoidal wave shape centered at zero volts, though it could be centered at another point. If it is centered at another point than zero volts, it is most often referred to as having a voltage offset. An AC voltage could have another wave shape besides sinusoidal depending on the application or components it is reacting with. The rate at which it changes direction is referred to as its frequency.
+The opposite of AC is DC where the current only flows in one direction. DC will have a voltage level in only one direction, either positive or negative, referenced to a common, ground or zero volts reference point.
+Mains power in many countries such as Britain, Australia and Europe is at 230v AC at a frequency of 50Hz, that is 50 complete cycles per second. North America uses 115v at 60Hz.
+\\
 [[http://www.allaboutcircuits.com/vol_2/chpt_1/1.html|http://www.allaboutcircuits.com/vol_2/chpt_1/1.html]]
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 ===== AWG =====
+American Wire Gauge is a set of standard sizes for wire diameter. It covers both solid and stranded wire.
-American Wire Gauge- This is not the same as Standard Wire Gauge. There is no direct conversion in that the ratio of radii SWG/AWG varies from 0.8 at 6/0 to 1.64 at 43.\\
+As the gauge number gets larger the wire diameter gets smaller. Larger wire is generally used for carrying higher current levels since larger wire has less resistance and so for higher currents less voltage is dropped over a given distance.
+In North America, extension cords are generally wired with 16AWG or 14AWG. House outlet wiring would generally have 14AWG or 12AWG wiring. In the UK, Australia and many other countries 2.5mm or 4mm wiring would be used in a similar fashion. Bus wires for DC or DCC may use large gauges such as these to supply a fairly constant voltage level (provides a low voltage drop over distance) around a large layout. Feeders to a track would be much smaller wires as current demands would be smaller. Relay coils and small wattage transformers may have gauges from 18AWG down to 28AWG. Wirewrap wire is generally 26AWG. While this paragraph is fairly general, it will give you an idea what to expect for wire sizes on a layout or simple projects. Better detail and recommendations can be found elsewhere in the Forum for a specific task.
+AWG is not the same as Standard Wire Gauge. There is no direct conversion in the ratio of wire diameter between AWG and SWG.
+\\
 [[http://www.hardwarebook.net/table/AWG.html|http://www.hardwarebook.net/table/AWG.html]]\\
 [[http://www.simetric.co.uk/siwire.htm|http://www.simetric.co.uk/siwire.htm]]