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Learning about electrical dohickies Answered

I'm not proud of this, I don't know very much about electronics, electricity and the components used. However, what I do know is that when there are three poky things on the end the thing-a-mabobber you either have to put it into a thingy with three holes or, if there are only two holes, you have to get a hammer and beat in the third hole. After that my electrical knowledge wanes.

So I'm trying to find an avenue to increase my knowledge about the subject but I'm having a hard time at it. I've checked out books from the library but, being that those books are written by engineers, they're coded so that only those who posses the engineers genome can understand them. I stopped by a local community college, explained to an instructor there what I was wanting to learn and after a few minutes he tells me that I'd have to spend the next year or so learning electrical theory before I could even get started doing what I'm interested in doing. Maybe he's right, but I just want to cover all my bases before diving in.

I have no urge to become an electrical engineer, but I would like to know things like how to repair an extension cord correctly and safely. I'd like to know how to hook up a small DC motor to an AC power supply, use a bread board to make blinking lights or something then transfer them to something more permanent. I'd like to know how to wire up a light table, know what rating of switch I would need and why. So nothing all that difficult, or should I say nothing I think is all that difficult.

I know the standard reply here is "just start playing with stuff" but considering that this is electricity and components can add up money wise, there is a risk of fire, and I have no urge to give myself electroshock therapy, I was wondering if anyone here could at least point me in a direction to start.

I've considered getting one of those electrical sets that you get for kids to learn with but I don't know if that's a decent place to start or not.

So any feedback would be very much appreciated.

Take Care,


P.S. I'm just joking about getting a hammer and beating in a third hole. Instead you get a pair of wire cutters and cut off the poky thing that doesn't fit ;)



Not only have I found oodles of great sites to start on thanks to y'all, or you'ns for those who prefer. But I also found a book. A book that I figured existed, though being the dip sh*t I can be I never bothered looking on Amazon. But I finally found "Electronics for Dummies". I swear I went to library, and a host of book stores looking for books like this and never saw one. It's like it was written for me! The capital 'R's' are even printed backwards. Pretty cool!

So I got a breadboard, and as many little electrical parts as I could safely shove in my pockets and run with before the police could arrive.

I am now on my way to build the doomsday machine that will enslave the world and turn you all into my lobotomized zombie minions.

So thanks again and I'm sure I'll be posting back here soon for advice, so until then ...

hail astro

Yay! I will be the cutest lobotomized zombie minion!

The response here has been overwhelming! I'd like to thank everyone for chiming in and for your advice I really appreciate it!

I've been following the links provided and reading those sites, specifically the really basic stuff. Most of it seem pretty clear cut, at least for now.

My next question might be a little more difficult so let me preface it but saying that I'm an architect and the only engineering I'm familiar with is structural. Structural is very "if you want this than you must have that". Example: If you want a beam you must have a column. If you have a column you must have a footing. (sure, you can have a bearing wall but it's an example)

There are also many rules of thumb that, as the architect, you can work into your design before the engineer gets on board. For example bar joist depth, the rule of thumb is for ever inch of distance plan on 1/8" of depth.

So my question now is this, is/are there similar ways of looking at electrical components? When I'm sitting there looking an empty bread board and want to make a dohicky turn on with a thingy, are there general "if this than that" kind of rules to follow? "If I have a dohicky I must have a contraption, if I have a contraption I must have a ...."

See, it's easy enough to read the definition of say, a capacitor, it's quite another thing to know when, why, where and what size you need.

I guess what I'm saying is that at this point I'm looking at electrical components much in the same way I see structural components and I'd like to know if I need to change the way I'm approaching this.

I hope that made sense, if it didn't let me know and I'll re-write it.


Sure...I mean, if I savvy your question--does everything in a circuit have a purpose? And is it understandable, and predictable? The answer is yes.<br /> <br /> But like an engineering question, the answer might be simple, or it might be very complicated. A component is like any structural element, it's use only makes sence in context.<br /> <br /> So lets use the <strong>capacitor</strong> as an example (since you brought it up) : A cap has certain characteristics that can be used in different ways--<br /> <br /> -- Caps store energy in form of a charge<br /> -- Caps tend to block DC, but pass AC and pulses<br /> -- Together with resistance (or impedance) they have resonance, and form a <br /> filter.<br /> <br /> ------------------------------------------------------------<br /> <br /> So you'll find capacitors in circuits doing various duties to take advantage of their traits. Here are a few:<br /> <br /> -- Coupling : caps are used between signal stages to block any offset voltages that are produced by the bias of the previous stage.<br /> <br /> -- RC (and LC, LCR) filters : By it's nature a coupling cap <strong>is</strong> an filter (it <strong>will</strong> always be followed by some sort of impedance.) Here's a nice simple calculator for designing high and low pass filters:<a href="http://www.muzique.com/schem/filter.htm"> RC filter calc</a> .<br /> <br /> -- Decoupling : Decoupling is a special application of a lowpass filter. It used to shunt unwanted high frequencies to the ground, and away from the signal path. Decoupling caps are most common in digital circuits, and help prevent oscilation and noise.<br /> <br /> -- Smoothing : Caps are a necessary part of most power supplies, due to their ability to store current.<br /> <br />

A point of notation, because it can be serious: just becauseone blade (wire) is marked <em>Neutral</em> do not ASSUME it has 0 potential (current). <br /><br />And one last little tip: All Grounds are not createdequal.... :-) <div id="refHTML"> </div>

Right.  That's the problem with Alternating Current -- the current flow runs through both wires, switching directionsixty times per second.

The problem is, there are not 2 hots and one ground on any of thenormaloutlets in the house. At least, there shouldn't be. One iscalled neutral because it is near the center of a 2 phase currentthatis split when it enters the house (two hots and one neutral, enterthehouse). This gets split and part of the house has one phase,andthe other part has the other phase. The neutral is <i>near groundpotential </i><i>but is not always 0 volts. </i><i>At least, that is how Iunderstood it last time I read about USA house current supplies.</i><i /><div id="refHTML"> </div>

A "Ground" is really just a reference point. And it needn't bereferenced to "earth" to still be a ground.

Safety-type grounds are "earth grounds," of course. But as younoted, even those don't always have zero potential...

I just meant that some confuse "neutral" with Ground. <br /><div id="refHTML"> </div>

Yep, and I agree...

Little wonder there--the old electrothingamabobs didn't have a separate ground.

indeed, and this whole idea that potential in AC <em>jumps</em> back and forth from wire to wire is not correct either, right? I mean, I understand the change of direction of current flow, but I also understood that to occur on the Hot and not on the neutral wire (that is, making the two reversed in function). Correct me if I have forgotten something (or read something that was not correct). <div id="refHTML"> </div>

Good question; I think we all struggle with these concepts. Here's my take:

The "Hot" conductor waveform fluctuates +-120V RMS relative to the "Neutral", which is ground referenced.

But the potential to each other is equal. If you choose to use the HOT as a reference base, the Neutral would appear to fluctuate +-120V. You can't tie it to earth (that's "already taken" in standard wiring), but as a separate reference it's technically valid.

Neutral then is safer (didn't write safe), because the environment (and the people in it) also has a potential very close to that earth ground. It's the reference itself, not any fancy transformer or wiring that makes neutral more...neutral.

So "Earth Grounds" are not arbitrary references (as I'm sure you know)--there are very good reasons to use earth as a ref. It's the closest thing to a universal "zero potential"  point and it's easily accessible for all buildings, HT towers, power plants, etc.

Ok, so then my answer to Kelsey was not <em>exactly</em> correct then? AT:<br /> <br /> <span style="padding-top: 4.0px;float: right;color: rgb(133,117,97);">Oct 15, 2009. 12:34 PM</span> <div id="refHTML"> </div>

Only that the potential of a current source depends on where it's measured; and what that measurement is relative to (pardon my grammar..)

It's easier to understand with DC-- you can have positive, negative and even elevated voltages, relative to a system ground.

Is the ground on a +-12V bipolar supply at zero, or is at +12V? (halfway between 0 and 24) Just moving the ground reference to 0V turns the bipolar supply into a unipolar 24V supply...

Still, It's not incorrect to state that Neutral is always at ground potential, if everything is wired correctly, and that's how you're measuring...

Part of this has to do with the definition of Alternating Current. If it's not swinging plus and minus relative to a midpoint reference, then it's "pulsed DC," not AC.

<em>Part of this has to do with the definition of Alternating Current. If it's not swinging plus and minus relative to a midpoint reference, then it's "pulsed DC," not AC.</em><br /> <br /> Yes, I understand that AC is an analog wave up and down, rather then an on and off scenario. AC appears as a wave on a scope, while pulsed DC would appear like <br /> <br /> <div id="refHTML"> </div>

Too bad your example is missing. The difference between AC and DC sine waves has a lot to do with the wave being symmetrically plus and minus relative to the reference voltage (+/- is the alternating part of AC, not the wave itself.)

Without nasty math, comparing the EMF (potential) of the two: The emf of the AC wave is the area within the curve; the emf of the DC wave is the area under the curve.

Due to it's shape, the AC wave clearly has more potential than the DC wave (it should, it's got all those negative voltages at hand.) So all sine waves aren't created equal.

(In the bottom row of the illustration, the AC is rectified so the peaks would be equal heights, but the potential of rectified AC is the same as normal AC.)


Well, I am still learning to use the old scope I have (or maybe it was too slow?). Last time I tested a line and it turned out to be a pulsed DC rather than AC it looked like this: <div id="refHTML"> </div>

DC Scope.JPG

Doesn't look quite right, does it? ;-) Even without all the documentation on AC, I can say empirically that US mains are + and - voltage--or half-wave rectification would only return half the line voltage, when I know for a fact it gets at least close to full voltage (depending on the current draw, caps used, etc.)

I wouldn't think even an old scope would be too slow for 60Hz. Something's off...

Oh my, I see the problem. That graph is of a pulsed DC line off of a 555 timer run off a battery. *<h3 style="color: Red;">blush</h3>* <div id="refHTML"> </div>

My little example went away_ _ _" <div id="refHTML"> </div>

You can thank Nikola Tesla for that.
I think.
Or was it Marylin Monroe?

Thank him for the lack of a seperate GROUND reference? That doesn't sound like something to be proud of.... ;-) <div id="refHTML"> </div>

<h3 style="color: rgb(255,0,255);">The sentence read: <em>You can thank Nikola Tesla for that.</em></h3> <div id="refHTML"> </div> <div id="refHTML"> </div>

I need to take a nap.

 You mean to say that you can't just hook up any wire anywhere? Sheeze! This is going to be harder than I thought!

(Note to self: buy electrical add on for brain)

Oh, you sure as heck CAN hook it up anywhere.

What's that? You want to hook it up WITHOUT catching yourself on fire? Hmm, this'll be a but more complicated then.


8 years ago

Yikes! White is Neutral and Black is HOT (in the USofA, anyway.)

(It's an easy mistake, as Black is normally GND in DC circuits...)

Argh.  I don't want to think about whether I've made thatmistake multiple times (as you suggest, I normally doDC electronics -- or I color match an existing outlet on replacement).

In any event, I am deleting and rewriting my entire reply above,correcting that dangerous error.

I don't do wiring often enough to trust my memory. So even though I'vemucked with a lot of projects and devices, I'm always checking to makesure it's right.

(Coincidentally, yesterday I just happened to be re-purposing an oldcomputer cord.)

In certain areas of the US of A, you'll find green, white, red, black,yellow, and/or blue!
A simple tester will go a long way.

Well, you'll find a lot of <em>imported</em> electrical cords... ;-). That's why I always test the plug / colorcontinuity with a meter before I wire something up. I've found someoddball colors, too.<br /><br />The USA spec for <em>extension cords</em> is still Black = hot, White = neutral, Green = GND. And even for wallwiring, <strong>white is almost always neutral</strong>.<br /><br />Still, just because the wires are color-coded doesn't indicate they arewired correctly. Testing is always the best bet (test the outlets, too.)<br /><br />Pic below is of an outlet (not a plug.) I keep this handy as a reminder.<br /><br />


Wow, this new widget really does drop spaces. A lot of spaces...

It seems to be ignoring the word-wrapping.

I didn't read everybodies replies, but I kinda scanned and noticedpeople giving suggestions about colors or wires and positive andnegative and so on.<br /><br />I cannot stress enough. Do NOT NOT NOT ever go off of color to determineany type of polarity (+ or -) or current or voltage and on an on. Youcould seriously injure yourself or others or start fires, damageprojects ect...<br /><br />I would start off learning how to use a multimeter if you're interestedin doing any electrical projects. After that, learning symbols andacronyms would be a good idea<br /><br />Check out this program (link is for download page) <a href="http://fritzing.org/download/">fritzing.org/download/</a><br />You can use that program to simulate a breadboard and instead of buyingpotentially expensive components and ruining them buy experimenting youcan do they exact same thing but on your computer. Then once you feelyou've learned a decent amount of electrical stuff you can try out theschematic maker or even try to design your own PCB. The possibilitiesare endless because it's all free. The only thing is that the program isin Alpha testing, so the creators(devs) ask that if you have problem orrun across bugs in the software that you report it to them so they canfix it.<br /><br />Good luck

One thing that has helped me in my quest for electronic understanding isthinking of the wires as pipes, and electricity as water. This makes ita bit more intuitive.<br />In your intuitive thinking, you'll want to remember that positive andnegative charges are more or less simple indications of direction offlow, and that in order to get a flow at all, it has to have a circuit(cyclical route) to follow, with your power source as the starting andterminating point.<br />Next is always remembering the important formula, V=I/R, where V =Voltage, I = Current (amps), and R = Resistance (ohms). As yourvoltage goes up, your current will also. As your resistance goes up,your current goes down. In addition, P = IV, power (in watts) is currenttimes voltage.<br />Now that you have this, you'll want a DMM to measure voltage, current,and resistance.<br />Those electrical sets kids learn with are needlessly expensive, and it'sdifficult to really learn a lot from them (in my experience). Better tobuild your own, and know exactly what components you're working with,and save a good bit of money besides.<br />Get yourself a breadboard, and maybe a soldering iron and solder. Find asimple project here, like one with LEDs or piezoelectric speakers. Trybuilding it, and try experimenting with variations.<br />Once you feel comfortable about the relationship between resistance andcurrent, branch off in learning about capacitance and inductance. Thosehave a lot more bearing in the world of AC, which is a totally different(and, in my opinion, more complicated) beast.<br />One item of importance is a diode. It allows electricity to only flow inone direction, allowing a million uses, like in a <a href="http://en.wikipedia.org/wiki/Bridge_rectifier">bridge rectifier</a> which can help change AC current to DC current.<br />Be careful with higher voltages. They're what drive the amps, and amps kill.<br /><br />

This bug that deletes spaces is killing me.

It's making me a bit nuts too o_0<br /><div id="refHTML"> </div>

I don't have a lot of time at this very moment to reply properly, butI want to at least say thanks to everyone that's has commented. Itall seems very helpful.

www.allaboutcircuits.com is a very good place to start. Takes it from a very basic level all the way up.

If you ever get stuck or have a question, I'm in the instructables IRC channel a lot of the time.

Damn, it got stuck on italics. Grrrr

[Please note:  This is a repost of my earlier comment.  I stupidly switched the color coding for home electrical wiring.  A mistake like that can potentially be dangerous, mainly because of the phase mismatch if you swap the two AC legs.  I am grateful to gmoon for correcting me, and for providing a very nice figure!]

What an awesome request!  You most certainly can learn enough about electricity or electronics to do what you want, andwithout taking a year of community college courses.  You will endup with a lot of gaps in your knowledge, and maybe even somemisconceptions (or at least over-simplifications), but you'll have agoodbaseline from which to fill those gaps.

Start with repairing extension cords.  That couldn't be easier,since the wires inside are color coded.  In the parlance of workingelectricians, black is "hot", white is "neutral", and green (or even uninsulated) is"ground" ("earth" to the Brits in theaudience).  With modern "polarized" plugs, the bigwide blade is "neutral."
Take a look at gmoon's very nice diagram.  So if you go to Home Depot and buyreplacement parts, now you know which wire to hook up to whichblade.  Beyond that, look for some basic home electrical repairbooks.  And don't cut off the poky thing!

For the rest, you might find that your best bet is to go to your publiclibrary, and look for books about electricity (especially projectbooks)in the "juvenile" section.  While the agelevel of the writing is probably going to grate on you, my point is onlythat those books are not written by or for engineers.  They don't make assumptions aboutmathematical background, and they tend to explain things fairlyqualitatively.  Look for books aimed at high-school age, not younger.

Once you've gotten a few simple projects done (breadboarding an LED, anRC-decay circuit, etc.), move up a notch. I got a greatbook,"Electronic Gadgets for the Evil Genius."  Some ofthe projects are great, and they have relatively step-by-stepinstructions to get you through it.  After building a few circuits,and seeing the schematics associated with them, you should develop atleast a sense of the patterns involved.

Good luck!

if you have skype, i'd be glad to video chat with you and teach youanything you want to know

You could look at <a href="http://www.google.co.uk/#hl=en&source=hp&q=electronics+tutorial&meta=&aq=0&oq=electronics+tuto&fp=1&cad=b"> web-tutorials</a><br />But you might be as well looking around here, e.g. <a href="https://www.instructables.com/id/Car_Mods/"> fiddling with cars</a> - a lot of those involve simple stuff.<br /><br />L<br /><br />