Bat, Dist, +, -

[t-west]

(Edit: sorry, can someone move this to electronics? thanks)

I've switched to a Flamethrower coil, and I'm going to admit some general ignorance -- what does + and - mean really. I'm trying to line the marks on the former coil (bat., Dist.) with the new + - marks, but then I got to thinking what's the difference between + and -?

Here's my theory: + means that the "juice" is moving from the Battery to whatever is marked + (like an input) while - means it's leaving the device headed to the next + inline (like the output -- in this case, the dizzy). Or, essentially, this is backwards. Anyone know?

--tom

 

[Lazy JW]

Don't be embarassed about your confusion, this can be a bit confusing at first.

+ means "positive" and - means "negative". But current actually flows from negative toward positive. It sounds backward, but I think that in the early days of electrical study that it was believed to be the other way, then later experiments showed that it actually does flow negative to positive. Of course there is now a theory called "hole flow" that postulates that it is the empty space that goes positive to negative. Bleh! I'm sticking with the negative to positive theory because that's what I was taught in electronics school in the military, and the actual results back it up.

On your distributor the + is connected to the battery via the ignition switch, and the - is connected to ground via the breaker points.

Of course there are the older Fords (pre 1956) that used Positive ground, and some British vehicles did too.

Are you still confused? I know I am

Joe

 

[t-west]

To clarify,

My distributor is connected to the battery via the + on the coil, then through the ignition, etc. (working backwards)?

If current flows from negative toward positive, then in theory, everything drawing current would need to have power come into it via its negative terminal and exit it via its positive terminal, heading towards it's next destination. In essence, in electric "peripheral" devices, negative (-) is the "input" and positive (+) is the "output?"

--tom

 

[Lazy JW]

Yup, you got it

Now the confusing part. As mentioned above, it is possible to design a DC (direct current) circuit to utilize a "positive" ground setup. This is where the positive side of the battery is connected to ground. I am not aware of any newer cars being built this way.

Not to worry though, troubleshooting techniques are the same, and the biggest concern is getting the coil polarity connected correctly because it was designed to be used only one way.

Just think of the ungrounded side to always be "hot" and you will be fine Another term for ground is "common". We won't get into AC circuits today

Joe

 

[t-west]

Okay, now I think you're trying to confuse me!

--tom

 

[Lazy JW]

Okay, now I think you're trying to confuse me!

--tom

No, really I am not. And which direction current flows isn't all that important for the average home mechanic. Just when you get into diodes, transistors, and designing circuits.

Just remember that in a negative ground vehicle (almost all of them are) the points connect to the negative terminal on the coil.
Joe