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73 votes
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Does wire color matter in electronics?

The colors do not matter electrically. A wire is a wire is a wire, regardless of the color of their insulation. The color of the wire itself may matter when you get into higher voltages, but that's ...
Passerby's user avatar
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60 votes
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Resistance of wire

Sometimes, a wire is negligible in terms of its resistance. Other times, impacts of the resistance of a wire can become significant. I'll first show the resistance of a wire, and how you can ignore it ...
比尔盖子's user avatar
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58 votes
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Is Ohm's law really accurate?

Ohm's Law says that the current through a resistance is the voltage across it divided by the resistance. The key point is that it is the voltage across the resistance, not the voltage of your supply, ...
GodJihyo's user avatar
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52 votes

Does wire color matter in electronics?

Wire colors are like comments in code, even for simple DIY projects. You're talking to your future self. When you take it apart in five years because it stops working, you will have forgotten ...
bobflux's user avatar
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38 votes
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What is a reasonable way to connect small wires?

For a good connection that can withstand lots of movement/bending, use: Solder Crimp terminals (either permanent "butt" connectors, or male and female terminals if you want to connect and disconnect)...
Bort's user avatar
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38 votes
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Connecting 10AWG wires to PCB

My general strategy for dealing with vibrating wires is to provide strain relief. I would consider adding holes in your PCB specifically for wire retention, like in the image below. You can use ...
Ocanath's user avatar
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35 votes
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Heating a wire with DC current; why is it hottest in the middle?

There are two effects going on. The heat sinking effect of the connections and the temperature coefficient on the wire. Initially the wire is all at the same temperature. You turn the power on and ...
Andrew's user avatar
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33 votes

What is this wire connector/terminal called?

That's an insulated bootlace crimp ferrule. Insultated so that there is no touch danger when fully inserted into the terminal block. The insulation covers the funnel which guides the strands into the ...
Transistor's user avatar
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31 votes
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Why is there no net current in a wire without a voltage applied?

Statistically, there are as many electrons moving in one direction as there are in the 180º opposite so there is effectively no net current. What we know as "current" is the movement of more ...
user134468's user avatar
29 votes

Is Ohm's law really accurate?

All models are wrong. Some models are useful. First, you should calculate the resistance of the wires (Whether thick or thin) and include that in your model. Provided the thin wire isn't too thin, the ...
The Photon's user avatar
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28 votes

Extra bare wire in USB cable

This is a shielding ground wire (or S-GND) which is left bare on purpose, so it makes contact with the foil. It has to be connected (crimped or soldered) to the metal casing of the USB receptacle / ...
Dmitry Grigoryev's user avatar
26 votes
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Extra bare wire in USB cable

That is the drain wire that helps carry charge off of the foil jacket and carries more current than the foil can. It is part of the shield/ground of the cable. As far as how to terminate it, that ...
Daniel's user avatar
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24 votes
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Why do these secondary transmission wires coil around the primaries?

They are spiral vibration dampers, most likely made from plastic material to prevent damage to the cable. The Spiral Vibration Damper is a motion control product used to dissipate aeolian vibration ...
jsotola's user avatar
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23 votes
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What does the pill-shaped 'X' mean in electrical schematics?

Cables FL1000B20-WHT and FL1000B20-BLU are twisted pair with additional shield. Look at these symbols:
Jakub Rakus's user avatar
  • 2,235
22 votes

Why is there no net current in a wire without a voltage applied?

Short answer: some textbooks are infected with a misconception, the idea that electrons always orbit the individual metal atoms. Nope. They'll also tell you that electrons only jump between atoms ...
wbeaty's user avatar
  • 11k
22 votes

Does wire color matter in electronics?

Wire colour matters! Not for the current running though the wire but for troubleshooting, safety, and others that may encounter any project. At powerline level voltages, national regulatory bodies ...
James's user avatar
  • 229
19 votes

Is Ohm's law really accurate?

Ohm's law is a model, that means it is aims at prediction of physical reality with a mathematical formula. As all models, it is valid only under certain conditions. First of all it is only applicable ...
Andreas H.'s user avatar
18 votes
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Soldering a high-power cable to a PCB

From the photos it looks like you are desiging a brushless driver for RC car , the RC car motor and batteries are sized for short pulses of high current and not continuous , so the limit in your case ...
ElectronS's user avatar
  • 3,239
18 votes
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1 kHz clock over long wire

So, the first problem will be that you need to drive that long cable! A 1km long piece of wire is simply a large load, and your microcontroller output will have a hard time changing the voltage on ...
Marcus Müller's user avatar
18 votes

Reason not to use aluminium wires, other than higher resistance

It is the primary choice in HV power transmission cables- aluminum with a steel core for strength. As well as the well-known issue of cheaply and easily making reliable field connections with small ...
Spehro Pefhany's user avatar
17 votes

What is a reasonable way to connect small wires?

I would solder them and then use three section of shrink-tube. One around each wire and after that a third one to cover all of them. But then I happen to have a drawer full of shrink tube of various ...
Oldfart's user avatar
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17 votes
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What are these teardrop-shaped loops in power lines for?

I always assumed it was a way to store slack in a cable like coax or fiber that can't be bent sharply without damaging it. I followed the "Snowshoe" link Michael posted, and it appears that ...
Duncan C's user avatar
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17 votes
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Is the bigger wire section always better from the electrical point of view?

Is there any case or application where using a wider cable section is worse? Yes, it may create the wrong characteristic impedance. Here I'm thinking cable (as per your question) and coaxial cable ...
Andy aka's user avatar
  • 462k
16 votes

1 kHz clock over long wire

You really need to think hard about what you really mean by "simultaneous". Over a span of 1000 meters, the concept does not extend down to the sub-ns regime. Heck, it would take a light pulse more ...
Dave Tweed's user avatar
  • 174k
15 votes

How to remove enamel from wire?

I had to strip 60 ends of 0.2mm enameled wire for my little project of dead-bugging and dumping a 32-pin EEPROM: By the end I arrived at a method of laying the end of the wire on a piece of smooth ...
spbnick's user avatar
  • 251
15 votes

Should wires be tinned to under the insulation?

NASA, in the NASA Training Program Student Workbook for Hand Soldering, page 9 et seq., say: ... adding solder to the wire until the tinning has reached no closer than 0.5 mm (0.020 in.) to ...
Andrew Morton's user avatar
15 votes

3 wires on a (bipolar) DC plug - what are they for?

There is two reasons. Remote voltage sense as tony suggests. And because some of these chargers are actually both barrel and center pin, making them have 3 conductors. The third conductor is ...
Passerby's user avatar
  • 73.2k
15 votes

Connecting 10AWG wires to PCB

Ferrules on each conductor, then into spring cage connectors on the PC board. I do a lot of work on very large earth-moving machinery and the field techs tell me that connections done that don't ever ...
Dwayne Reid's user avatar
  • 23.9k
15 votes

Do wires go bad?

Wires can break if they are moved regularly. Any metal item can suffer from metal fatigue if it is bent repeatedly, and copper wire is no different. In places where vibration or repeated bending is ...
Simon B's user avatar
  • 19.5k

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