Hey all, new to the forums, been involved in the hobby most of my life.
I have done some searching of the forums and found many questions but few correct/complete answers regarding Basic Electrical Fundamentals. I spent 8.5 years in the navy as a nuke electrician and spent many a 6 month deployment sketching and bench testing solid state electronics. I also taught B.E. at the Naval Nuclear Power Prototype (NY) so I am quite comfortable talking on the subject.
My question is this, how much interest is there in having a moderately detailed Basic Electricity Reference Thread/Sticky on this forum? If there is enough interest I can easily type one up with some pictures and post it. If not that I can easily field individual questions.
Dave Loman
My site: The Rusty Spike
"It's a penny for your thoughts, but you have to put your 2 cents in.... hey, someone's making a penny!"
Welcome to the forum. Some people like tutorials, but for the most part they are either too long or skip too much. There are some good books on the sunject, but they take time to read and we are into other hobbies. They also tend to spend too much time on aspects of the disciple that are not included in the question. Seldom do I want to learn a subject, what I want is an answer.
I do like having people on this forum who can answer my questions in short consise answers that do not go into so much background I get lost. That is what many of us try to do in areas where we do know a little something.
I would certainly welcome your assistance in the area of electricity. As to a tutorial, maybe for others but not me.
David,
Three words: GO FOR IT!!! I've read and dug and scratched and clawed to understand what I know...and it STILL isn't all that much.
Personally, I enjoy tutorials. I have three on my web site that I wrote myself and have included them all on the forum, at one time or another.
Most of the books and links that I have read on electricity and wiring usually start out okay. But the author soon forgets the novices in his audience and quickly jumps by leaps and bounds into more sophisticated topics on the subject - making assumptions that you know more than you do.
So, David, to answer you question again - I would personally welcome a tutorial on basic electrical fundamentals whole-heartedly. Since I'm a visual person, pictures and diagrams are a plus in my book.
David, this is just a suggestion. Jon Grant has recently done a very nice step-by-step tutorial on weathering freight cars:
http://www.trains.com/trccs/forums/962238/ShowPost.aspx
The one thing that I really like about Jon's approach is that it comes in "installments". I think this method makes it easier on some folks who might feel overwhelmed about a particular topic...say, like electrical principles? The installment method of a tutorial allows the reader to "ruminate" or digest the material in small doses, then move on at his or her's own pace. Joe Fugate is very good at this approach with his tutorials.
Anyway, I hope that's a help...
Tom
BTW: to the forum!
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
I could sure use a basic electric tutorial. Go for it.
A couple of things.
First, here's another one of those signs. Always happy to have more people on board.
Second, if it's good, it may earn a spot in our "hall of fame", otherwise know as the New Compilation of Widely Useful Threads
Again, welcome to the forum.
Life is simple - eat, drink, play with trains!
Go Big Red!
PA&ERR "If you think you are doing something stupid, you're probably right!"
I guess - on one hand - I'm sorta surprised, and - at the same time - not suprised at the answers given on the interest in the aforementioned topic - both on this thread and the similar one posted on the Layout forum. Even if I were only moderately interested, I think it would still be great to have a "bookmarked" reference on a particular topic to refer to when the occasion arose to use that information.
I've found that understanding certain things has lead me to desire to understand other things. Then again, I usually was interested in understanding the topic in the first place.
Well, I guess you can't feed a person...unless they realize they are hungry. But then...you can always offer them a "snack" and see if they'll stick around for more.
(Okay, enough pontificating from the peanut gallery. )
Yes, very interested. Here are some things to get the ball rolling.
1. What is "single pole" as in "single pole-double throw switch"? What does it mean, how does it function, etc?
2. "Double pole"?
3. "Double throw"?
4. A resistor keeps current from flowing. How do you know what size to use?
5. How do you wire a diode? Is the wiring for a LED the same?
6. While we're on it, what is a diode?
I guess those are about as Basic as you can get. Obviously, I need some help. Please send some help.
FT
Not to step on your toes Claymore , but I'm bored so I'll try and answer these.
BTW- I think your tutorial is a great idea.
ft-fan wrote: Yes, very interested. Here are some things to get the ball rolling.1. What is "single pole" as in "single pole-double throw switch"? What does it mean, how does it function, etc?2. "Double pole"?3. "Double throw"? A single pole switch has one pole thet either switches a single contact (single throw) or switches between two contacts (double throw). Usually with a neutral position where neither contact is active. This would be used to turn something on or off typically. A dual throw is essentially a set of single throw switches linked together mechanically to switch two contact between two poles, or sometimes one pole but dual pole single throws are not that common. A dual pole dual throw would be used for a reverseing switch (reverseing electrical polairity) 4. A resistor keeps current from flowing. How do you know what size to use?Simple answer..., Ohms law. But that is probably beyond most folks on this board.Ohms lawV=I x RR=V/II=V/RWhere V=volts I=current in amps and R=resistance in ohms 5. How do you wire a diode? Is the wiring for a LED the same?A diode and an LED are the same electricaly but an LED emits light. A diode is a PN junction device. It will let electrons flow in one direction but not the other (zenars not included). A diode has to breakdown the PN junction, usually a .7 volt drop, but beyond that does not resist current flow. Therefore to use a LED you must use a resister in series to limit current and prevent it from blowing. This is where ohms law would come into play. If you have a 16 volt source and want to hook up a diode you must limit the current by the proper amount. If the LED has a max current of .05 amps then you use ohms law to find the resistor value. Lets add a safety margin and say we want to run a diode off of 16 volts and its max rateing is .05A (or 50mA). calculate for .04 A at 16v... R=V/R so we divide 16v by .04 amps and get 400 ohms. Now one other thing to consider is will the resistor handle the heat dissipation (in Watts)Ohms law also says Watts = I x VSo if I is .04 and V is 16 (actually 15.3 after the voltage drop of the diode (LED)) the resistor will need to be able to dissipate .64 watts. Most resistors are 1/4 watt or 1/2 watt so for this example you will need a special resistor that can dissipate more then .64 watts (which will most likely be a 1 watt, the next highest common wattage rateing for resistors)Simple eh. 6. While we're on it, what is a diode?I guess those are about as Basic as you can get. Obviously, I need some help. Please send some help.FT
A single pole switch has one pole thet either switches a single contact (single throw) or switches between two contacts (double throw). Usually with a neutral position where neither contact is active. This would be used to turn something on or off typically.
A dual throw is essentially a set of single throw switches linked together mechanically to switch two contact between two poles, or sometimes one pole but dual pole single throws are not that common. A dual pole dual throw would be used for a reverseing switch (reverseing electrical polairity)
Simple answer..., Ohms law. But that is probably beyond most folks on this board.
Ohms law
V=I x R
R=V/I
I=V/R
Where V=volts I=current in amps and R=resistance in ohms
A diode and an LED are the same electricaly but an LED emits light. A diode is a PN junction device. It will let electrons flow in one direction but not the other (zenars not included). A diode has to breakdown the PN junction, usually a .7 volt drop, but beyond that does not resist current flow. Therefore to use a LED you must use a resister in series to limit current and prevent it from blowing. This is where ohms law would come into play. If you have a 16 volt source and want to hook up a diode you must limit the current by the proper amount. If the LED has a max current of .05 amps then you use ohms law to find the resistor value. Lets add a safety margin and say we want to run a diode off of 16 volts and its max rateing is .05A (or 50mA). calculate for .04 A at 16v... R=V/R so we divide 16v by .04 amps and get 400 ohms.
Now one other thing to consider is will the resistor handle the heat dissipation (in Watts)
Ohms law also says Watts = I x V
So if I is .04 and V is 16 (actually 15.3 after the voltage drop of the diode (LED)) the resistor will need to be able to dissipate .64 watts. Most resistors are 1/4 watt or 1/2 watt so for this example you will need a special resistor that can dissipate more then .64 watts (which will most likely be a 1 watt, the next highest common wattage rateing for resistors)
Simple eh.
I am also an electronics tech willing to help if I can, but I don't come to the MR forum that often.
chad thomas wrote:Not to step on your toes Claymore , but I'm bored so I'll try and answer these.
No toe steppin observed! I'd be quite the fool if i though I was the only one who could answer questions in this arena!
ft-fan wrote: 6. While we're on it, what is a diode?
But I will field this one. A diode is the equivilent to a piping systems check valve, a valve which only allows fluid flow in one direction. A diode will conduct current only if the + and - voltages applied to it are applied on the correct sides of the diode.
Clear it up a little?
Alright Ladies and Gents, the first section of Basic Electricity 101 is up. More to follow as my kids/wife allow me time :) Till then, please critique my work so I may make it better. Questions about specific subjects will also help guide the direction the tutorial takes.
http://therustyspike.hyperphp.com/BE101/BE101_00.html
Thanks for the effort putting this together, David. I look forward to reading this when I have a chance.
I made it through the first couple of sections - i.e. 1.1 and 1.2. I like what you've done so far. Just a few minor suggestions, if I may:
Section 1.1
m = milli = 1/1000u = micro = 1/1,000,000K = kilo = 1000M = mega = 1,000,000
Section 1.2
David, my purpose is NOT to get nit-picky but to make things a little more obvious and intuitve for the newbie. Am I stepping over the line?
tstage wrote: Don't make assumptions that folks automatically know what m (milli), u (micro), K (kilo), and M (Mega) are. It would also be helpful to know what these terms mean: m = 1/1000u = 1/1,000,000K = 1000M = 1,000,000
m = 1/1000u = 1/1,000,000K = 1000M = 1,000,000
Good call, will add a table!
tstage wrote: Schematic - Point out which symbols are what. For instance: "In this schematic, a battery (left) is supplying 12 volts worth of electrical potential and a resistor (right) is offering 1 ohm of resistance to the flow of current." You can eventually figure it out but the "left"/"right" help to do that quicker and say to the reader, "Oh, that's a battery symbol." and "Hey, that's what a resistor symbol looks like."
Actually this is in progress as I am working on a Legend in Photoshop.
tstage wrote: I'm assuming you are not able to display the symbol "omega" on your web site?
Yeah I got my butt whooped by fonts last night and I gave up. I will make a small 10px x 10px graphic to use instead. Its on the todo list :) thanks though.
tstage wrote: Section 1.2Why are you solving for "Ia" and not "I"?How is Resistor R1 able to "drop" all 12 volts? Through heat?
Ia is a force of habit as everything I have done in the past decade represents Armature Current, or current of the main generator, as Ia, or more simply, total Current. I suppose the sub characters on the various I's to come need some explaining.
As for R1, yes, a resistor performs no other function than converting energy to heat.
tstage wrote: David, my purpose is NOT to get nit-picky but to make things a little more obvious for the newbie.Tom
David, my purpose is NOT to get nit-picky but to make things a little more obvious for the newbie.
No worries, I asked for feed back and I have thick skin :)
All right! Another tutorial. There is always something new to learn. Love this hobby. I'm game.
Regards,
I've made it 1/2 way through the next section:
1.3 Power
Current: I = V/RVolts: V = I*RResistance: R = I/V
That way, substituting Ohms law for current in Example 1 is easier to see: Power = V * I (or V/R), Power = V * V/R, Power = V2/R (Sorry, Dave, I don't have "the power" for squaring.
I'll keep plugging away at it. David, you are doing a good job.
claymore1977 wrote: tstage wrote: I'm assuming you are not able to display the symbol "omega" on your web site? Yeah I got my butt whooped by fonts last night and I gave up. I will make a small 10px x 10px graphic to use instead. Its on the todo list :) thanks though.
this might help with most (maybe all) of the symbols that you couldn't get. It's pretty simple to do - pretty much replace the greek letter/symbol with the code that's in either the "Entity", "Decimal", or "Hexadecimal" on your page. Browsers will figure it out (and it'll look fine too)
-Dan
Builder of Bowser steam! Railimages Site
NeO6874 wrote: this might help with most (maybe all) of the symbols that you couldn't get. It's pretty simple to do - pretty much replace the greek letter/symbol with the code that's in either the "Entity", "Decimal", or "Hexadecimal" on your page. Browsers will figure it out (and it'll look fine too)
Excellent, I use www.w3schools.com as my primary html, xhtml, css, etc resource and didnt find anything there. Thanks for the link!
And Tom, thanks, I standardarizededed all the eqn's plus added a simple explaination of whats going on step by step. Thanks again. More to follow after I get home tonight.
Looks good, but I am a little bleary-eyed after one time thru. I am "electrically challenged", so I will have to read through it a few times to get it. The math is easy, it's the concepts that are tough. A couple of questions did come up as I read through it.
At the beginning you give us the definitions and all the abbreviations for that, then your first diagram uses I to measure current (granted it is Ia, but it is still I), and that was rather confusing, as above you said current was measured in Amperes, so I was looking for an A to describe that. Can that be cleared up somehow?
All your expamples show the voltage going to the negative side of the battery to be zero. Is the goal of any circuit to get the voltage coming back to the battery down to zero? What happens if this does not happen? For instance, if you put a short wire from + to -, assuming the resistance of the wire is 0, does your battery immediately run dead, or explode or ???
In your last example, if you used a 500 ohm resistor instead of a 600 ohm, would the bulb actually explode, or just immediately burn out? Would it be a good assumption that the lower sized resistor you put on the bulb make the bulb burn out faster (ie. 400 ohm vs 500 ohm)?
I think this will be quite helpful. Thanks for the effort to put it together.
Alrighty FT, let me field your questions here and then think about how to best integrate them in to the tutorial.
ft-fan wrote: At the beginning you give us the definitions and all the abbreviations for that, then your first diagram uses I to measure current (granted it is Ia, but it is still I), and that was rather confusing, as above you said current was measured in Amperes, so I was looking for an A to describe that. Can that be cleared up somehow?
I am going to change the Ia back to I once I get a chance, but as for I representing A, that's going to have to stay the same and here's why. A could be used as the Current variable in the equations, but A is also the abbreviation for Amperes. So the following EQN would be very confusing:
12V / 8&Omega = 1.5AIs that 1.5 amps or 1.5 * A ? This is why 'I' was chosen (not my be, but by the electrical gods of long ago) over 'A'.I will put a blurb about 'Why I?!?' in the tutorial, thanks!
ft-fan wrote: All your expamples show the voltage going to the negative side of the battery to be zero. Is the goal of any circuit to get the voltage coming back to the battery down to zero? What happens if this does not happen? For instance, if you put a short wire from + to -, assuming the resistance of the wire is 0, does your battery immediately run dead, or explode or ???
Not really 'the goal' per say, as more like it's a definite thing. If you have a 12V source, then all 12V WILL be dropped by whatever components are in the circuit. All the circuit analysis in the tutorial is calculated in an 'ideal world' In an ideal world, wires don't have resistance, in the real world they do. In an ideal world, batteries don't have an internal resistance, but in the real world they do (that's why they get hot during charge/discharge). So in an ideal world, if you where to short a battery or other power source from + to - then the following application of Ohm's law would exists:I = V / RI = 12V / 0 ohmsI = infinite current.But, in the real world wire has resistance, albeit very low:I = V / RI = 12V / 0.001 ohmsI = 12,000A
And since 0.1 Amps can kill, 12,000A would probably make you living impaired very quickly. The battery would probably run out of energy in a few nano seconds, and the wire would vaporize.We haven't talked about it yet, but Power can also represent Power Loss. In the short circuit configuration you mentioned, the battery is giving up a massive amount of energy and the only destination for that energy is heat and the only destination for that heat is the wire. The wire will probably not be able to shed that much heat that fast and melt, or just skip the liquid phase altogether and go straight for plasma.Short circuits is the reason why they invented Circuit Breakers :)I'll put in a realworld/idealworld explination somewheres.
ft-fan wrote: In your last example, if you used a 500 ohm resistor instead of a 600 ohm, would the bulb actually explode, or just immediately burn out? Would it be a good assumption that the lower sized resistor you put on the bulb make the bulb burn out faster (ie. 400 ohm vs 500 ohm)?I think this will be quite helpful. Thanks for the effort to put it together.FT
Bulb lifespan is completely upto the manufacturer and is really hard to quantify accurately. A light bulb is, at its basic roots, an energy conversion machine... just like EVERYTHING that us humans ever made. And accordingly, any machine (with a few exceptions) can probably handle being operated at >100% for a little while, but the overall lifespan of said machine is probably going to be greatly reduced.As for the lightbulb, there is a current limit that will cause a bulb to instantly blow, but without distructive experimentation (MUWAHAHAHA) you may never truly know where that current limit lay.My reccomendation is to shoot for 75% to 85% of the max current rating for the device. You will get about 75%-85% luminosity but probably double the lifespan of the bulb.And yes, the more current you run through a bulb, the less efficient it is and will burn out sooner.
I will weasel all this info in somewhere, thanks for the Q's
claymore1977 wrote:Alrighty FT, let me field your questions here and then think about how to best integrate them in to the tutorial. ft-fan wrote: At the beginning you give us the definitions and all the abbreviations for that, then your first diagram uses I to measure current (granted it is Ia, but it is still I), and that was rather confusing, as above you said current was measured in Amperes, so I was looking for an A to describe that. Can that be cleared up somehow?I am going to change the Ia back to I once I get a chance, but as for I representing A, that's going to have to stay the same and here's why. A could be used as the Current variable in the equations, but A is also the abbreviation for Amperes. So the following EQN would be very confusing:12V / 8&Omega = 1.5AIs that 1.5 amps or 1.5 * A ? This is why 'I' was chosen (not my be, but by the electrical gods of long ago) over 'A'.I will put a blurb about 'Why I?!?' in the tutorial, thanks!
Thanks for the reply. Just a statement that in the diagrams I represents current flow as opposed to A being the measure of that flow in Amperes is kind of what I was talking about. I think that would alleviate some confusion - I had to look at that several times the first time to figure it out.
Thanks for the explanations. There may be hope for me yet.
I like the improvements! Your step-by-step explanations are a big help (for me) in following and understanding what you are trying to convey. And I especially like the section on voltage drop for custom tuning lightbulb brightness and longevity. I'll probably go through it all again.
David, keep up the good work (in progress )....
As I was typing up my last response to FT, I realized I had made a grievous error in all the equations posted. Voltage is not supposed to be represented with a V for the exact same reason, Amperage is not supposed to be represented with an A. Voltage is supposed to be E and current is supposed to be I. I added this clarification to the definitions at the top of the page and updated all equations. The theory and numbers stay the same, just V became E.
Sorry!
cwclark wrote:This is really all fine and dandy, but you know you'll have to write a book for electricity 101. There's no mention of capacitance reactance, resistance thru parallel and series resistors, (I know..divide the parallel resistors by .1) wattage, microfarads, induction coils, resistors, capacitors, integrated circuits, transistors, diodes, zener diodes, bridge diodes, transducers, thermistors, heat sinks, mofets, coil relays, the relationship between voltage output related to the number of transformer coils, the difference between direct current and alternating current and how to measure it with a multimeter or oscilliscope, ...well, you get the picture...the list goes on and on...I took electronics in college for two semesters and still I don't know the nitty gritty of a lot of electrical principles... I think the best way for folks to learn is to get a good book on electricity and study it, and even then it's gonna take a long time to get good at it.....chuck
I agree some and disagree some. Most of that stuff will be covered, eventually. Of all the interest I have recieved on the subject, almost all were geared towards lighting, not making custom PCB's. That being said, the simple subject will be covered first, and if the demand is there, more complex subjects later.
There are certain subjects that I will not type up as books are probably a better place for learning. Once the reader is at that level though, they don't need my 'Translated to Engilsh' tutorials.
I think the best way to learn is to grab a few concepts and sit down and blow up a light bulb or two and learn hands on. I taught BE for several years and noticed that most people will only get so far into a book before they get discouraged as even basic elec fundamentals can get complex in a hurry... people need to play and get their LED glowing to perk enough interest to actually care how a capacitor impacts DC and AC circuits.
Just my $0.02 anyways. Like I said, I am not done writing yet!
claymore1977 wrote: As I was typing up my last response to FT, I realized I had made a grievous error in all the equations posted. Voltage is not supposed to be represented with a V for the exact same reason, Amperage is not supposed to be represented with an A. Voltage is supposed to be E and current is supposed to be I. I added this clarification to the definitions at the top of the page and updated all equations. The theory and numbers stay the same, just V became E.Sorry!
I wouldn't go to grievous! I don't recall ever (well that's a long time, but...) seeing current represented by 'A', but rather always by 'I'. But I think that I have seen voltage represented by 'V' quite often. It has been a while (a few whiles, actually) but I'd say that I saw 'E' more in the physics class side, and 'V' more, or at least some on the engineering side. At least, I know that I remember Ohm's law as V=IR, for what it is worth!
Jeff But it's a dry heat!
I agree, but I also saw that physics/elec eng relationship, but I had it pounded it in to my head in Nuclear Field A school to never use V, as 12V could mean 12 Volts as easily as it could mean 12*V
Vail, Az eh? I spent the first 18 years of my life in Florence, AZ just up rt 79 from Tucson! Howdy neighbor! :)
claymore1977 wrote: I agree, but I also saw that physics/elec eng relationship, but I had it pounded it in to my head in Nuclear Field A school to never use V, as 12V could mean 12 Volts as easily as it could mean 12*VVail, Az eh? I spent the first 18 years of my life in Florence, AZ just up rt 79 from Tucson! Howdy neighbor! :)
And I lived for 8 years in Columbia, MD!
And the world gets a little bit smaller...
Which do you like better?