Interesting video on voltage drop

[richard5933]

There have been a number of threads over the past years discussing chasing down electrical problems. Here's a video I found helpful explaining some basics for checking for voltage drop.

https://www.youtube.com/watch?v=qdaOSiScEu8

What was most helpful to me was when he described using it to help run down the problem at about the 7-minute point of the video. Some of the video is basic information, but overall I think that it will be helpful for many, especially those newer to working on vehicle electrical systems.

[dtcerrato]

Good video Richard, thanks.

[David Anderson]

Great tips.  Thanks for sharing.
David

[richard5933]

This guy has a bunch of videos, all on related topics. Many of them would have helped guys trying to diagnosis electrical problems. Hopefully I'll remember some of this when I need it next.

[blue_goose]

Bad info !!
Jack

[richard5933]

Bad info !!
Jack

Please explain.

[blue_goose]

WHICH WAY DOES CURRENT REALLY FLOW? | Electronic ...
https://www.electronicdesign.com/blog/which-way-does-current...
If you said positive to negative, you are wrong. Then you remember that current flow is a charge of electrons moving in a conductor and they go from negative to positive.

[richard5933]

WHICH WAY DOES CURRENT REALLY FLOW? | Electronic ...
https://www.electronicdesign.com/blog/which-way-does-current...
If you said positive to negative, you are wrong. Then you remember that current flow is a charge of electrons moving in a conductor and they go from negative to positive.

Got it - the guy made a mistake. Not sure it affects the overall lesson in the video which was testing for voltage where there shouldn't be any in an attempt to find a problem.

[Dave5Cs]

The second video was actually better than the first one. It came up after the first one. He did explain how they flow from negative to positive. Interesting.

[Jim Blackwood]

Yes, but what about the flow of "holes" from positive to negative? It gets really complicated as you keep looking closer and closer so sometimes it's best not to look too close.

Jim

[buswarrior]

It is not easy to make accurate training materials, it is even harder to find accurate training materials, when you are being paid to try...

Safety videos with people wandering the background with no personal protective equipment, technical training with technical errors, voice overs mixed in trying to repair whatever audio that didn't work out live, obvious ego issues with "the star", slang terms vs proper names...

And on and on.

Tough world to try to learn something new.

Happy coaching!
Buswarrior

[MagnoliaBus]

Honestly you don't need to know the direction of currrent flow to troubleshoot our simple bus circuit.

To help understand how it came to be explained the reverse way read this excerpt from "Hughes - Electrical and Electronics Technology - 10th edition":

All electrons have a certain potential energy. Given a suitable medium in
which to exist, they move freely from one energy level to another and this
movement, when undertaken in a concerted manner, is termed an electric
current flow. Conventionally it is said that the current flows from a point of
high energy level to a point of low energy level. These points are said to have
high potential and low potential respectively. For convenience the point of high
potential is termed the positive and the point of low potential is termed the
negative, hence conventionally a current is said to flow from positive to negative.
This convention was in general use long before the nature of electric
charge was discovered. Unfortunately it was found that electrons move in
the other direction since the negatively charged electron is attracted to the
positive potential. Thus conventional current flows in the opposite direction
to that of electron current. Normally only conventional current is described
by the term current and this will apply throughout the text.

Every books, schematics, etc., follow this principle. Electrical engineers learn this in school.

Learning how every components relate to each other is more important than knowing electron flow.

Just to prove that the world revolve around this reverse flow; try to reverse the polarity of a multimeter leads on a battery, it will show a minus voltage...

[Jeremy]

I can see how knowing which way the current actually flows isn't necessary to the layman working with basic circuits - but presumably it quickly does become important when trying to understand only slightly more complicated circuits that include things like diodes or LEDs? Or not?

Jeremy

[chessie4905]

Or the direction of flow in ac.

[MagnoliaBus]

In AC, it goes both ways (it reverse) 50 or 60 times every seconds.