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Voltage: Parallel and Series Circuits (2019)
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1. Introduction: LED Sign -
2. Failed Series Circuit
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Check Your Understanding: Failed Series Circuit -
Mini-Project: Voltage Investigation
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3. Parallel Circuits
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Upload a photo of a parallel circuit used to power multiple independent loads. -
Mini-Project - Shared Voltage Nodes
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Check Your Understanding: Shared Voltage Nodes
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Wire Coloring
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Check Your Understanding: Parallel Circuits
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4. Power Panels - Managing Parallel Circuits
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Mini-Project: Mounting to the Terminal Block
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Mini-Project - Terminal Block with Jumper
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Check Your Understanding: Power Panels
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Unit Project: LED Sign
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Upload Photo: LED Sign
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Upload Block Diagram: LED Sign
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Wire Coloring
Explanation Wire Coloring
You have probably noticed that wires come in different colors. The color is technically just color -- it doesn't mean the wires are made of different material, etc. Instead, electrical technicians choose wires of different colors to indicate important things about each wire.
Here are some examples:
You may have noticed that red wires in our lessons always connect to the positive terminal of the battery, and black wires always connect to the negative terminal. This is the same thing as saying that the red wires connect to a +3.3V voltage level, and the black wires connect to a 0V voltage level (also called the ground, common, or COM voltage). This makes it easier to see the parts of the system, and to keep straight which wires connect to which areas.
This is related to what it plugs into on both ends, but is much easier to identify. The white wire in this set of three motor wires is damaged, but the red and black are intact. This is important information for troubleshooting -- in this case, knowing that the data wire is broken means the team doesn't have to look for a software error -- it's clear that the controller signal won't go through (white wire broken) even though the motor powers on (red and black wires OK).
Some wires are very long, or pass behind walls, through long pipes, etc. Using wires of different colors (or color patterns) tells you which wire is which on each side.
These wire color systems only work if people follow them consistently. If someone gets lazy and uses a red wire where they should have used a black wire, someone in the future may treat it like a red wire, and connect it to the wrong place. This can damage the system, or injure the person who was working on it. Nobody wants that, so technicians are usually very insistent that wire coloring systems be followed closely..
Finally, note that the coloring systems may be different between regions (for example, wires connected to 0V terminals are usually black in the US, but blue in Europe), and also by profession (robotics often uses red wires, but electrical systems for houses don't), or even by company (one company may use brown wires, while another might use striped green ones). What is important is knowing what system is being used for each project, and following it 100% of the time!
