Talk to me about electricity as you would to a toddler

LeVeL

LeVeL

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There are two subjects that I cannot comprehend for the life of me: chemistry (failed basic in college... twice) and electricity. I can live without the former quite easily but the latter would be good to know. For instance, I could use some basic knowledge right about now to work on the Miata.

Specifically, I need to do two things:
1. Replace my lame horns with proper loud ones.
2. Diagnose a possible short - one speaker is either quiet or silent until I turn the volume way up and after that it works fine at all volume levels.

I have been looking for info online but even when the explanations begin with "well, that's really easy..." they lose me within the next two sentences because I have no idea what anything is. For example, they will mention measuring volts, amperes, or ohms, andI have no clue what the differences are or how to measure them or what that would even tell me. I've never soldered anything and I bribe my friends to do little electrical projects for me (I can change a lightbulb and plug stuff in though!).

With that, it's time to learn. Forget wiring for dummies - I need wiring for braindead goats. Where do I begin? FinalGear brain trust, halp!!1!
 
Volts is what's required to power something (shut up, it's how I understand it). Amps is the energy consumption. Measuring resistance is exactly as it says it is. You seeing how much something can resist power in the unit of Ohms. If there's no resistance or very little found (like 1.0 or tenths of an ohm) it's typically a direct short. What I suggest is you get a decent multi-meter and get Ugly's electrical reference book. It might be a little overkill but, it covers most all things electrical.
 
I think your speaker issue is either a connection that is corroded, the rheostat in the radio, or a speaker that is on it's way out due to a tear or sag in the foam that allows it to move. The first and third can be checked by pulling the speaker out and inspecting it, which can clear the second by elimination.


If it is the wiring to the speakers, I would just change it out. I know it will be a slight pain, but it is not like you have 4 speakers and subs.
 
93Flareside said:
Volts is what's required to power something (shut up, it's how I understand it). Amps is the energy consumption.
Click to expand...

Persons A and B each have 20 wooden planks to move. Person A takes two at a time and walks slowly, while person B takes one at a time but runs with it every time. In the end, it took both 10 minutes to finish their jobs.
Person A did the job using twice the amps but half the volts. In the end they developed the same watts.

This is the reason why you need lots and lots of amps on the 12V side to convert 12V DC into 230V AC.


The same analogy could be used for rpm, torque and horsepower btw. A diesel spins slower but does the same job as the equivalent horsepower Honda.
 
The speaker could be busted. I had similar issues with a speaker that had one of those tiny little wires leading to coil broken. Sometimes, when given enough volume it'd "settle" into place of contact and start playing normally. If that's the case, I wouldn't waste my mental health trying to repair it. Best tested with speaker out of the car, to isolate the issue.

Perc said:
Persons A and B each have 20 wooden planks to move. Person A takes two at a time and walks slowly, while person B takes one at a time but runs with it every time. In the end, it took both 10 minutes to finish their jobs.
Person A did the job using twice the amps but half the volts. In the end they developed the same watts.
Click to expand...

Haha, I like this analogy, and I want to elaborate. It is close enough already, with one important omission that isn't quite as neat: neither person just chooses how many planks to carry, they always take as much as possible. Like, maybe there's an air drag that slows them down, the fast person can't sustain his speed (the speed is volts) with more than one plank (amps), the slow person can sustain his speed with two planks.* That air drag is your circuit resistance.

Also, in electrical circuit the planks don't just move from A to B, they go A via B and back to A, losing voltage in the process. Hence the "circuit". So the people in this analogy just carry the planks around :lol: And there is just one part of the route where resistance is really high (like your speaker) and the rest of the route is really easy (wires), but still they can only carry as many planks as that bottleneck allows. This is why the source determines the voltage, but the load determines the current. The analogy starts to be a bit iffy by now :?

And then if you accidentally short circuit the load, so that the whole route becomes really easy to move through, both persons take a HUGE LOAD of planks and are still able to move at their full speed, which causes a lot of stress on the route, damages all the roads (your wires get hot and burn). So what do you do to prevent this? You make a weak bridge along the route. If there is too much stress, the bridge just falls apart and all movement stops, the rest of the road is preserved. That's your fuse, which is rated for a specific amount of amps (amount of planks) before it breaks.

* Kept thinking about it over lunch, and realized that the striked-out part is actually wrong. Faster person (more volts) will be able to carry more planks (amps) through the same resistance (ohms). Of course that means that he's doing work with higher power.
 
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Now I can't get the image out of my head of a capacitor as a bloke chopping up the planks, keeping a small stack as a buffer and handing them out evenly.

Good analogy too, getting a shock can indeed be like being hit with a plank.
 
They're good fun to play hot potato with.
 
Power is when things start to get weird and the plank analogy gets more complicated. Where

power=P, measured in joules/second
voltage=V in joules/coulomb
current=I in coulombs/second
resistance=R in ohms
and V=IR,

playing around with algebra results in

P=(I^2)*R =(V^2)/R

hence why you need to get the resistance of your replacement speaker right lest it result in putting out more power than the system is meant to, given a constant input voltage.

And this is even before we get into the (unintended?) pun of plank=Planck.
 
1. Horns would be really easy to install. Disconnect your originals and reuse the same plug. The plug will have two pins (if male) - one is power the other is ground. Your new horn will come with two wires, power and ground. With a set of pliers, or a knife, expose each of the wires and connect them to a couple of cable terminals (female or male, depending on what your original horn plug is). Connect and you are done.

2. The speaker issue sounds like a rheostat going sticky/bad, meaning the problem won't be with the actual speaker. If it is the speaker, their wiring is exactly the same as the horn.
 
Louder horns can mean more current draw. If your stock wiring isn't rated for it, you get melting and potentially fire.

So, no, not necessarily just a quick easy install.
 
Is that realistically going to happen though? I doubt he will be running massive train horns, he will probably get some Hella Supertones. And even if there is more draw, unless he lays on the horns for prolonged periods of time, it wouldn't cause the wiring to melt...much less cause an actual fire.
 
_HighVoltage_ said:
Is that realistically going to happen though? I doubt he will be running massive train horns, he will probably get some Hella Supertones. And even if there is more draw, unless he lays on the horns for prolonged periods of time, it wouldn't cause the wiring to melt...much less cause an actual fire.
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That depends on whether his vehicle has a horn relay. You can actually get steering wheel fires on some cars by uprating the horns to something like a little Stebel Nautilus pair and pressing the button. A lot of OEM horns have very little current draw and the rest of the horn circuit is very specifically calibrated for that low draw. So, yes, it's a concern even if you're just throwing in some FIAMMs or Hella Supertones.

There are cars that have smaller wires and less current handling capability in their horn circuits than my 919 does, with its weedy little scooter horn.
 
Even if they have fuses for the horn circuit? I have a pair of much louder Cadillac horns on my relayless MR2, and so far it hasn't either caused a fire, and I have tested the fuse thanks to some careless installation.
 
Yeah, even if they have fuses. Horn circuit design is where a lot of makers skimp.

However, most stock car horns can interchange with little to no ill effect. It's when you get into aftermarket horns that you can hit problems. All I'm saying is to check the power requirements of a prospective aftermarket horn system before you try installing it.
 
Gotcha. And given how many old GM cars are in junkyards, I find the aftermarket horn industry pretty silly.
 
Labcoatguy said:
Gotcha. And given how many old GM cars are in junkyards, I find the aftermarket horn industry pretty silly.
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Well, not everyone wants to have a horn that blasts in the key of Awful. :p

I find salvaged X300 and X308 horns to be a better choice. :D
 
LeVeL said:
For example, they will mention measuring volts, amperes, or ohms, andI have no clue what the differences are or how to measure them or what that would even tell me.
Click to expand...

I enjoy thinking about it as water going through pipes.

Voltage = water pressure
Amperage = water volume
Watts = the amount of work that the water could do as it's voltage times amperage (think of a water mill)

So a low voltage, high amperage power line can do the same amount of work as a high voltage, low amperage one. It's why electric water kettles in Europe (240V) require half the amps that they do in the US (120V), which is why they're uncommon here.

Ohms are a unit for measuring resistance. Think of it like how easy it is for water to get through a pipe.

This is a good read: https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law
 
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Thanks for all the responses! Fascinating reading material.

Yes, the horns are Hella Supertones. I recall reading once that it's not quite plug-and-play due to the horns' additional power over stock. That said, I think my current horns are Stebel Nautilus - they were installed when I bought the car so I'm just going by what they look like without taking them out.
 
Too silent, and it will steal all the wooden planks from the car's alternator. What is needed is something that can produce its own power and be heard 25 miles away.


The 5.4L Hemi V8 will not burden your four pot's alternator. Most importantly, the sound will not only get the attention of the asshole who cut you off, but also cause their ear drums to explode; thus guaranteeing said asshole will never forget their thoughtless and unforgivable transgression. Collateral? Fuck them, they were probably going to fuck you down the line anyhow.
 
Spectre said:
Yeah, even if they have fuses. Horn circuit design is where a lot of makers skimp.
Click to expand...

What do you mean by that? They uses fuses overrated in respect to the wire gauge? I find it hard to believe.

Anyway, NB miata seems to have a horn relay and a 20A fuse. If your new horn is under 20A (leave some headroom), you should be ok. Double check the relay and the fuse first, though.
 
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