# Understanding Electronics Basics #2

Discussion in 'General Electronics Chat' started by cowboybob, Mar 26, 2012.

1. ### Muttley600New Member

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I see what your getting at, by adding a - we are getting a different value to exponents
A bit like milli (my dino) walking backwards & getting bigger

Ignore this, it's wrong isn't it

Last edited: Apr 10, 2012
2. ### Muttley600New Member

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Just got the factorial thingy, can't believe I didn't see it earlier
Having time to absorb info makes a massive difference

On the morrow guys

3. ### KeepItSimpleStupidWell-Known MemberMost Helpful Member

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-2^2 is a trick question. Mathematics treats it as (-2)^2) or (-2)(-2) or 4

Other places treat it as: (-1)(-2)(-2) or (-1)(4) = -4

Yea, two answers for the same question. So, USE PARENTHESIS!!

An odd number negative numbers multipled together means the answer is negative.
An even number of negative numbers multipled together means the answer is positive.

_____

Graphs
We can label the axis any way we want as long as their is a relation. Your first exposure was voltage, time; db and time and frequency and amplitude.

I just picked coordinates which are supposed to be symmetric and would encompass the plate. The same co-ordinates that might exists on a mill with a digital display. http://www.amazon.com/mitutoyo-brid...=2025&creative=165953&creativeASIN=B0006J3JFS

And what do you know, this one has a Z-Axis and has BOLT CIRCLE CALCULATIONS. The one I used was probably one of the first ones made and was X & Y, no Z and not much on the fancy side, but is sure is useful.

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5. ### MikebitsWell-Known Member

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Akk, your killin me with all this math. Glad I became a firefighter Only math I have to worry about is knot and rope strength.

6. ### KeepItSimpleStupidWell-Known MemberMost Helpful Member

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MIKE: You don't know the half of it with regards to math. Without any foundation it's been really tough.
CBB: I used a couple of links to Wolframalpha in these threads before.

CBB, Graham: It's going to be a rough week. Last week was too. Tomorrow's problem: The narional pharmacy can't count, Pills were 80 short for mom and when they had to count to 12, they counted to 18.

CBB: Asleep (sin & Cos): http://www.suitcaseofdreams.net/trigonometric_functions.htm#A2

Last edited: Apr 10, 2012
7. ### cowboybobWell-Known MemberMost Helpful Member

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<EDT>DSL was down from last night til a few mins ago (or so I thought). Wrote this on last night's posts. Sorry if I've repeated the mantra, but repeat it I did. My apologies. CBB

NO. NO. NO. Extremely fundamental misunderstanding here.

Confusing? Yes. The point is that proving that a -1 time a -1 is a plus 1 isn't easy to do in a way that is utterly convincing.

So, I'll take the leap and just state it: -1 time -1 (or -2 times -2 or ANY negative number times another negative number) is ALWAYS a positive number. ALWAYS. Trust me.

Except, apparently, when a "Wolfram Alpha" math engine is used. I've got no idea what that's all about and I would suggest you pretend you never heard the name.

For our meager purposes, I state again:

One negative multiplier yields a negative answer
Two negatives multiplied together yield a positive answer.
Three negatives multiplied together yield a negative answer.

I.E., An Even number of negatives multiplied together yield positive answers.

An Odd number of negatives multiplied together yield negative answers.

Whether you believe it or not, any other usage will give you the WRONG answers.

Some things simply rely on derived results as proof. That or just plain blind faith...

Good mornin', by the way.

Last edited: Apr 11, 2012
8. ### Muttley600New Member

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I'll take it on this

Morning CBB

I'm buried in logs at the mo, at this rate, I reckon i'll be another week but I'll get there

I'll give you both a shout when I've caught up again

Last edited: Apr 11, 2012
9. ### KeepItSimpleStupidWell-Known MemberMost Helpful Member

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See this (order of operations): http://mathforum.org/library/drmath/view/57375.html

Now you can see a fundamental rule I like to follow. Determine what world you are in before you make any assumptions! Example:
Typical electronics: The red wire: (+), The black wire (-); Thermocouples: The red wire (-), the other color (+); US house wiring: The black wire (Hot), the white wire (neutral)

When I did an Explorer's Post at HP and I was still in High school, I argued with the mentors about the black wire and the fuse and I was right.
Our groups project was the second assembled and the first to work. I seem to remember one defective part and one tiny trace missing. The trace could have fell off. The layouts were done using the obsolete taped (red, black, blue) method .

Note the last two paragraphs here: http://en.wikibooks.org/wiki/Arithmetic/Order_of_Operations

Yes, -2^2 is -4 unless you happen to be using Excel. Excel got it wrong. (-2)^2 seems to be always 4, so the moral of the story is to use parenthesis.

Last edited: Apr 11, 2012
10. ### cowboybobWell-Known MemberMost Helpful Member

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Little story.

Had the opportunity to build my own house. The whole magilla. Design,foundation, framing, siding, roof (no interior weight bearing walls), etc. Did the plumping, wiring, sheet rock (the art of mudding eluded me to the end), flooring. You name it.

Inspections were a trial.

After I wired it, using 10 gauge everywhere (was gonna to the ECO-man thing with 24VDC solar, but gave up that idea when I saw he cost, but stuck with the 10 gauge), stapled the romex every 18", had the distribution box squared away and immaculate.

The county inspector toured and tugged, and at the distribution box commented that he thought the job had been done by a professional. I was exceedingly pleased.

He then pointed out that I had the wiring backwards. All of it. He politely informed me that black was not ground, but hot.

My introduction to things electrical was electronics. Thought that said it all about electricity in general.

Gotcha. Knew that thoroughly. Goes for cars too.

And where were you 32 years ago when I needed that info?...

Beware of hubris.

Last edited: Apr 11, 2012
11. ### KeepItSimpleStupidWell-Known MemberMost Helpful Member

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That's way cool. The wierdest repair project I did was pointing a chimney. Not fun AT ALL. I had to remove 3 layers of brick and I put back only two. It was too high to accept a cap. I was able to borrow mortar tools.

I haven't yet figured out a way to memorize the Blue/Brown colors in the IEC Electrical cords. I always have to hold it in front of an outlet and by knowing that the narrow socket is hot, use an ohmmeter to trace it back.

Thermocouples got me.

12. ### KeepItSimpleStupidWell-Known MemberMost Helpful Member

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I guess I got lucky. My father trained as an Electrician and had a very short stint working for a commercial company. I never asked him how he got involved with electronics, but he used to fix car radios and TV's for friends when they were tubes. At that time it was usually pretty simple. Pull the tubes or guess which ones, test them at home or your local convenience store, buy a replacement locally (at least 4 places to buy). Install and hope for the best. He did do at least two car engine swaps. He did start struggling with the 5 transistor car radios, but pretty much with my help (as a kid) we could fix them. So I got exposed to House electrical, car electrical, electronics, small engine and automobile mechanics very early. One of my early projects was a a carb rebuild on a 1968 Chrysler. That car was kept for 17 years. I kept a car that long too doing nearly all the repairs including major ones.

Last edited: Apr 11, 2012
13. ### cowboybobWell-Known MemberMost Helpful Member

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You and I are of a feather.

If it weren't for being able to fix stuff and make it last well past its normal life time, I would have had to make 3-4 times the income that it was my lot to make in this life.

So I guess it worked out OK.

14. ### Muttley600New Member

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Great story's guys, warms the heart
KISS, leads you were on about colours, from CBB's house wiring story, I take it each country has its own colour codes? Blue & brown over here are blue: N brown: L (easy to remember things like that, have a picture of a brown animal that bites if you touch it)

Been feeling rough & shivering since lunch time but I could melt an igloo at 200yrds with my temp, drank about 5ltrs water since this afternoon.eek now I'm here sweating it all back out, s'gonna be a long night

& CBB, that was a major thing to completely build a house from scratch, respect due my friend, no matter how you wired it

The rebuilding & keeping old cars running I can relate to, done a few old land rovers myself, had the one out of a scrapyard & kept it fifteen yrs before selling on

Last edited: Apr 11, 2012
15. ### Muttley600New Member

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So we all like to save money.lol
I'll never be rich, I enjoy the job I have too much, I was explaining to new chap, it isn't a job as such, more of a lifestyle choice where you become part of the community over the years

As long as I can afford my hobbies (read bike & tronics) I'll be content
So what other things do you two get up to?
I know KISS likes building old electrical stuff back up

16. ### KeepItSimpleStupidWell-Known MemberMost Helpful Member

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Old anything back up. I use 36 Year old lawn mowers and an even older snowblower and we have a 1950's stove that gets used regularly. My father and I put an AC in the house. After 38 years, it was still running. I put an AC in my car from a box, Same failure (hose crimps) every 8 years. Try 17 years on the original front brake calipers and still going. Oh, I gave that 17 YO car away to the dealer and it was a get-away car twice and the cops came visiting. I didn't notify motor vehicle that the car was sold.

17. ### cowboybobWell-Known MemberMost Helpful Member

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We obviously aren't doing our "share" for the economy, are we??!!

The three amigos.

Take it easy, Graham. You don't sound so good. Hopefully it'll be a quickie fever and you'll be fine in the AM.

18. ### Muttley600New Member

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Are you a relation of mine or are we just leading pararell lives.lol
My mower is 19yrs old, just due a overhaul
My father & I rewired my house
I gave motorbike to scrap dealer in return for engine, it was used in a robbery & police checked it out, I too didn't update log book.....won't be doing that again

19. ### Muttley600New Member

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Im doing my bit, just spent £500 on luggage system for my Candy (my motorbike)
It is funny how we met up

Feeling weak as a kitten this morning, temp better, stopped shivering & sweating just feel like I've run a marathon, no energy, just going to have soak in bath before work, I have this weekend off, Lou puts it down to me working/pushing myself too hard

20. ### cowboybobWell-Known MemberMost Helpful Member

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Mornin', Graham. Glad you're feeling better.

Thinking of doing up a sim that uses tubes (valves) for the heck of it. Don't see that much, anymore. Maybe a simple power supply for starters.

21. ### Muttley600New Member

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I remember that phrase.lol
Feeling lots better, got to see my dad in the morning then I'll get stuck in again