Electrical Tips for Rookies

[Al Skierkiewicz]

Originally Posted by Sparks333

Red is ALWAYS positive in electical systems, and you should color-code your wiring correspondingly. Black,or sometimes green, but mostly black, is Negative (actually ground, but it's easier to think of it as negative sometimes)
White is signal, and, unless you use other sensors, that's it.
I had a math teacher try to jump a car. Melted his battery, he did. Sparks

Sparks,
I don't want to make a big deal here but so people don't get confused I need to say these few things.
For First robots, the rules state the use of red for wires connected to battery positive and black for wires connected to battery negative. This is a convention for most electronic wiring but other colors are used all the time by designers. Measure first to be sure.
The term "ground" is sometimes used for "signal common" or power supply common but the term implies that somewhere the signal common is actually attached to ground. In AC power distribution this wire is green or green with a yellow stripe and it must connect to a rod or pipe in the ground. Ground may or may not be the power negative terminal. No connection between battery and robot frame are allowed even though many electronic systems will "ground" the common point to the frame.
Although Red and Black wires are used for power wiring and motors on First robots, the red and black wires between the speed controllers and motors can actually be tied opposite the convention depending on the direction of the speed controller or Spike. Again always measure, you may find 12 volts when measuring between a motor black lead and the battery black lead.
Other colors are used all the time and the only way to be sure is to check with the manufacturer, wire vendor or by measuring.

[Al Skierkiewicz]

Oh, By the way, black is the wire color for the "hot" in 120 volt AC house wiring. In three phase power systems, black wire is used very often for all phases with some kind of indicator as to which phase the wire represents. Black is also commonly the wire color of both sides of 220 volt house input wiring.
Red in house wiring is commonly used for "switched" power wiring or for anything the electrician chooses. When pulling in multiple circuits in a single conduit or raceway, different circuit "hots" will use a combination of colors (i.e.black, blue, red, yellow, etc.) with white as the neutral and green as ground.
Color codes vary across the country and municipalities so even the above colors may not apply in all locations.