Electrical diagrams 101 ?

[sugarwood]

https://learn.sparkfun.com/tutorials/capacitors/all

I've been doing some reading on capacitors, relating to a non-automotive subject. I came across a few basic diagrams and thought it may be worthwhile to take the first step in reading automotive electrical diagrams. Basic electrical troubleshooting is my favorite aspect of automotive DIY. Testing wires for continuity, testing if a switch is good, then testing is power is getting to the motor, applying power directly to a motor to determine if the motor is dead, etc. But, I've never used an electrical diagram.

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

For example,

The ===/+++ thing is a capacitor that can hold a charge.
The long and short lines are the power source battery.
The circles and line are a locking switch
The zigzag lines are a resistor of some sort (LED light, etc)

When the switch is down, the battery loads the capacitor
When the switch is up, the capacitor empties its electrons towards ground.

[Trackrash]

Who knew that motion gifs would run on Pelican.

So now you need to explain all the components and what is happening. I see you have done that.

However the wire from the battery to the cap isn't turning yellow when energized.

[theiceman]

Electrical guys stay quiet, but a good learning opportunity is figuring out why the resistor is there

[sugarwood]

Originally Posted by theiceman

Electrical guys stay quiet, but a good learning opportunity is figuring out why the resistor is there

It's the thing getting powered, like an LED light ?

[timmy2]

Simple RC circuit, add a 555 timer to make it flash continuously.

[Walt Fricke]

CDI is fundamentally sort of like that diagram.

[theiceman]

Originally Posted by sugarwood

It's the thing getting powered, like an LED light ?

think about ohms law,,, how much current is needed to power an led ... and how much resistance is in an led...

[T77911S]

i work on radar for the FAA.
a CD is very much like the PFN (pulse forming network) In the transmitter.
our new radar is digital, the old one had a vacuum tube that was about 3ft tall.

[MBAtarga]

Originally Posted by theiceman

think about ohms law,,, how much current is needed to power an led ... and how much resistance is in an led...

E = I / R

As R (resistance) decrease, I (current) goes to infinity where E (Voltage) > 0.
I cheated - 4 years of EE at GT.

[sugarwood]

Originally Posted by theiceman

think about ohms law,,, how much current is needed to power an led ... and how much resistance is in an led...

You sound confused.
Did you read the link?

For example, in the circuit below, a battery can be used to induce an electric potential across the capacitor. This will cause equal but opposite charges to build up on each of the plates, until they're so full they repel any more current from flowing. An LED placed in series with the cap could provide a path for the current, and the energy stored in the capacitor could be used to briefly illuminate the LED.

The diagram is of a circuit that powers an LED bulb.
Why does it have a resistor?
B/c that is the thing being powered!
That is the entire point of the stupid circuit. Duh.

[MBAtarga]

Originally Posted by sugarwood

The diagram is of a circuit that powers an LED bulb.
Why does it have a resistor?
B/c that is the thing being powered!
That is the entire point of the stupid circuit. Duh.

I'm not sure you understand the purpose of the resistor based on that comment.
What is the voltage drop across the LED? What is the current in the wiring assuming the battery is 12V?

[Geneman]

This would be fascinating to hear expanded upon by you electro-jocks. i am SEVERELY electron flow challenged, even though I have been soldering together kits from Radioshack since i was ten or so... but i still bnever understood why the hell your need all these resistors, diodes, caps, even considering a transistor mechanism makers me cringe with horror and results in a blank stare ( even though I am quite efficient at programming CAR-T cells, immunotherapies and Gene jockeying..) ... carry on on pleasse! Frank

[theiceman]

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 .

[motorstereo]

If you're "electrically challenged" like me, pick up Rob Siegel's book "the Hack Mechanic Guide to European Automotive Electrical Systems". It's kind of an idiot's guide to electrics and it covers such rudimentary topics as how relays work, how to test your alternator, how to jump a relay, guide to DIN numbering standards, troubleshooting a circuit etc.

looks like our host even sells it!

[MBAtarga]

Originally Posted by theiceman

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 .

Yes - and depending on the wire gauge - without that resistor either the wiring or the LED is going to go open circuit. This is basically what a circuit breaker in your house does - limits current flowing through wiring.

[john70t]

Originally Posted by theiceman

Electrical guys stay quiet, but a good learning opportunity is figuring out why the resistor is there

Good call.
Wouldn't that make the wire the only resistance in the circuit, allowing full current to pass through it?
(aka direct short to ground)

That would last as long as it takes for the wire to melt.
I've seen a battery melt a hole though a dented hood with people sitting on it. Big fountain of sparks.

Crispy crunchy wires isa no good.

[mike sampsel]

but where is the imaginary part of the impedance?

[911obgyn]

It’s the faucet you turn down to limit flow.
Or inline pressure regulator or tiny oriface

[ChrisHoover]

There is no load on the circuit without a resistor. A no load circuit is otherwise known as a short. Changing the value of the resistor will change the brightness of the LED.

[70SATMan]

Technically not true. Even the wire and the LED represent a "load",,,,,

Just not for long, LOL.