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-   -   Electrical diagrams 101 ? (http://forums.pelicanparts.com/porsche-911-technical-forum/1074919-electrical-diagrams-101-a.html)

T77911S 10-15-2020 03:59 PM

the resistor is limiting the current.

Bill Douglas 10-15-2020 04:03 PM

I only know what I need to know with electricity.

But I think capacitors are amazing.

T77911S 10-15-2020 04:08 PM

although looking at the ciricuit, and its been a loooooong time since I have thought about basic ELEC, the LED will light with the SW in both positions.
although momentarily off until the CAP charges up. with no resistor in series with the CAP and no known value, it would probably charge almost instantly.

in electronics wire is normally not taken into account.
It is possible it "could" be considered in very low voltage circuits.

the LED IS a load. it does have a voltage drop across it. diodes are normally about .7v, I think an LED may be higher.

sugarwood 10-15-2020 06:06 PM

Quote:

Originally Posted by theiceman (Post 11065758)
the purpose of the resistor is to limit the current going through the led.. keeps circuit current low.. forward biased diodes have very little resistance and require very little current to light, without the resistor the higher current flow would burn it out .

Are you even looking at the same diagram?
The only thing in the entire circuit is the capacitor and the LED.
There is no separate resistor !!

GAJon 10-15-2020 07:17 PM

Quote:

Originally Posted by sugarwood (Post 11052975)
https://learn.sparkfun.com/tutorials/capacitors/all

There may be others who are interested in the next step of reading diagrams.
Is anyone willing to post and explain a very basic electrical diagram relating some some simple aspect of the 911?
Like a window motor, for example

https://cdn.sparkfun.com/assets/d/2/...e042000002.gif

I don't want to steal this other users post, but he has a good schematic of the window motor circuit. Power Window Switch Schematic.

If you follow the lines, you can see the traces apply either forward bias (positive voltage) to the motor or reverse bias (negative voltage). The switch just changes the polarity. DC motors are neat because they can run forward or in reverse just by this simple change. They are really not much more complicated than that for a basic intro.

These cars were developed in a pretty basic age as far as car electronics go. I think the most complicated issue is knowing where all of the wires go and which circuits are tied to which. The actual functioning of the circuits is pretty straight forward.

tirwin 10-16-2020 10:15 PM

Quote:

Originally Posted by Bill Douglas (Post 11066009)
I only know what I need to know with electricity.

But I think capacitors are amazing.

When I was in college my roommate was a EE. One day I was sitting in the floor of our room studying. My roommate was sitting near me building something with a pretty big array of capacitors. I was positioned between him and the door to our room.

All of a sudden I heard a pop and he jumped over me like an Olympic hurdler and ran out of the room like he was on fire. I found him sitting in the hall and his lips were blue.

And that’s why to this day I think it’s helpful to have an EE friend around to teach the rest of us about electricity. :D

sugarwood 10-17-2020 06:01 AM

Quote:

Originally Posted by GAJon (Post 11066220)
I don't want to steal this other users post, but he has a good schematic of the window motor circuit. Power Window Switch Schematic.
.

Excellent post.
First reply that is actually on topic.

The battery wire goes through 2 fuses, #17 & #18
Why is one yellow and one red?

Wire then goes into the J relay.
Ignition switch closed, power flows through 85/86,
which then closes 30/87, allowing current to flow to window switch E39/E41.
Finally reaching the window motor at V15.


http://forums.pelicanparts.com/uploa...1298316365.jpg

http://forums.pelicanparts.com/uploa...1298316347.jpg

sugarwood 10-17-2020 06:07 AM

Quote:

Originally Posted by GAJon (Post 11066220)
If you follow the lines, you can see the traces apply either forward bias (positive voltage) to the motor or reverse bias (negative voltage). The switch just changes the polarity. .

Can you explain how you read this? How does the diagram show the 2 different states a window switch can hold?


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