# vcc vdd vss terminology

**URL:** <https://community.sparkfun.com/t/vcc-vdd-vss-terminology/12613>\
**Category:** PCB Design\
**Created:** [September 17, 2009, 1:04am UTC](https://community.sparkfun.com/t/vcc-vdd-vss-terminology/12613 "2009-09-17T01:04:36Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![haxby](https://avatars.discourse-cdn.com/v4/letter/h/ee7513/32.png) [@haxby](https://community.sparkfun.com/u/haxby)\
**Post date:** [September 17, 2009, 1:04am UTC](https://community.sparkfun.com/t/vcc-vdd-vss-terminology/12613/1 "2009-09-17T01:04:36Z")

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I have a circuit that uses a number of rails. Namely 5v, 12v, 3.3v

What is a good way to handle the terminology in Eagle?

From the sparkfun eagle library I have been adding ground, and vcc “components” into my diagram but they don’t differentiate the different voltages… What is standard practice in this area?

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**Author:** ![theatrus](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@theatrus](https://community.sparkfun.com/u/theatrus)\
**Post date:** [September 17, 2009, 2:00am UTC](https://community.sparkfun.com/t/vcc-vdd-vss-terminology/12613/2 "2009-09-17T02:00:09Z")

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The supply and sparkfun libraries contain “3.3V” etc symbols, which you should use (plus its more specific). Note that the supply libraries prefix with +, whereas Sparkfun does not (and that does matter when you use both ;)).