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glossary:glossary_g [2017/02/16 10:17]
glossary:glossary_g [2018/12/16 11:29] (current)
Mike Forrest
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 ~~NOTOC~~ ~~NOTOC~~
 [[start|Return to main Glossary index]] [[start|Return to main Glossary index]]
 +===== Gerber =====
 +A Gerber is a 2D binary vector image that describes every single layer of the PCB design. For instance, one Gerber describes the silk screen while the other describes the top, copper layer.
 ===== GIT repository ===== ===== GIT repository =====
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 ===== GPIO ===== ===== GPIO =====
-General-purpose input/​output ​(GPIO) ​is a generic pin on an integrated circuit or computer board whose behavior ​— including whether it is an input or output pin — is controllable by the user at run time. GPIO pins have no predefined purpose, and go unused by default.+General-purpose input/​output is a generic pin on an integrated circuit or computer board whose behaviorincluding whether it is an input or output pinis controllable by a program or script being run.  
 +GPIO pins (generally) ​have no predefined purpose, and go unused by default. Normally these are Tri-State pins.
 ===== GPP software ===== ===== GPP software =====
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-Is a common point in circuits ​normally 0 volts, but can be higher than 0 volt.+Electrical circuits (normally) have a common point from which voltages are measured.  
 +Historically this was the Ground (aka Earth), and could also have been the return path for electric current. 
 +In modern '​mains'​ AC power supplies, the '​Earth'​ line has a safety purpose and the '​Neutral'​ line is the '​Live'​ current return. NB: The Neutral is connected to Earth, somewhere further back in the supply system. 
 +Most modern low voltage and low power electronic ​circuits ​are NOT referenced to the Earth, but that name or Ground (aka GND) persists as the reference point, but more correctly its name is '​0V'​. The power supply modules for these circuits are said to be '​floating'​. Floating power supply modules ​can sometimes ​be identified by the use of a 2 wire connection to the mains. No harm will happen if the 0V line is connected to Ground. 
 +However, above a certain threshold of Voltage or Power or where a metal case/​chassis is used, modern regulations mean that an Earth connection is required and those power supply modules will use a 3 wire connection to the mains. An example of this is the MERG DCC power block
glossary/glossary_g.1487240235.txt.gz · Last modified: 2017/02/16 10:17 (external edit)