Simple Workings of a Transformer

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Jadnashua

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The better inverters make an actual nice, clean a/c signal. Mid-range ones make a stepped square wave, and the cheapest just make a noisey square wave. Most of them are nasty, though, and some things won't work well with the power they provide. They also tend to make a huge amount of electrical noise and rf. None that I"m familiar with reverse polarity to generate the wave, though.
 

Geniescience

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Invertor. DC-to-AC.

jadnashua said:
The better inverters make an actual nice, clean a/c signal. Mid-range ones make a stepped square wave, and the cheapest just make a noisey square wave. Most of them are nasty, though, and some things won't work well with the power they provide. They also tend to make a huge amount of electrical noise and rf. None that I"m familiar with reverse polarity to generate the wave, though.
off-topic, I'm wondering if a cheap invertor made for car lighter plugs can be used to charge a new Nokia cell phone without damage (to the Nokia).

David
p.s. also off-topic.
jwelectric said:
....Have you learned how to transform DC?
Huh? clarity please, if you want to ask a direct question instead of addressing the subject as a subject matter expert. Or, just be a subject matter expert and share what you know, gently.
 

Jadnashua

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For the cost of an inverter, (while maybe useful for various things), I think you'd be better off with their car charger cord. I'm lusting after their new N95...maybe when a carrier picks it up to subsidize (ATT listening?).
 

JWelectric

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geniescience said:
jwelectric said:
Have you learned how to transform DC?
p.s. also off-topic. Huh? clarity please, if you want to ask a direct question instead of addressing the subject as a subject matter expert. Or, just be a subject matter expert and share what you know, gently.

I did clarify the question here
jwelectric said:
abikerboy said:
Yea...it's called an "inverter"...lol!!! In the early days of electronics, it was called a "vibrating coil"... it was used to synthesise ac voltace out of a dc input by creating a chopped sign wave. Sorry guys, I just couldnt resist!

Does not an inverter work by reversing the polarity of the DC voltage applied to the transformer or in other words by alternating the polarity of the DC voltage.
 

Abikerboy

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jwelectric said:
Does not an inverter work by reversing the polarity of the DC voltage applied to the transformer or in other words by alternating the polarity of the DC voltage.
Im not sure about the newer ones, or the ones made in recent years. The older ones would just "chop" the wave...you could actually measure a positive and a negative voltage at the 110 volt output. The old ones even up through the 1970's and I think some even up into the 80's (unsure about this though) used the vibrating coil, then the "chopped" 12 volt feed was sent through a step up transformer to increase the voltage to 110 volt. There was no positive or negative on the input. Both wires are black with alligator clips to attach them to a battery. The vibrating coil is not electronic, so it doesnt care which way you feed it. The voltage was never stable, and the frequency would vary quite a bit as you put more load on it. I have a very old one here...it belonged to my uncle that died in 1975 if that gives you any idea of its age...when you put power on it, it buzzes loudly from the vibrating coil, and it gets very hot even with no load on it. Its only rated for 75 watts, so all Ive ever used it for was to charge an electric razor, or to run a small lamp on it when camping out. Im not brave enough to plug anything electronic into it.
 
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Abikerboy

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geniescience said:
i have a 1st generation invertor but I'm wary about using it on a new Nokia. Unless I hear that new devices can handle a dirty wave signal.

david
I wouldnt be brave enough to try it myself, though it actually might work. If it were me, Id just go to Wally world and buy the car cord that fits the phone for about $8 If you find out that it will or will not work, I would be curious to know.
 

Jimbo

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An inverter takes the car's DC battery voltage and outputs an AC waveform. Most commonly sold inverters take the 12VDC and output 120VAC. We should stop talking about polarity with an AC wave because it is not relevant.

Your charging cube for the phone takes a regular household 120 VAC and makes a much lower voltage, DC, to charge the battery. Why would you start with a car battery, invert it up to 120 AC, then "wall wart" it back to low voltage DC???? Why not just plug the phone in directly with a car adapter?
 

Geniescience

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it's a new phone, and the battery is so good they don't give you a car charger with it. Recently I did need to charge it, once, while in my car fro several hours. I later found an AC plug instead of using that old "toy" invertor. I had left the phone uncharged and out of service for a few hours.

((I have never used this inverter, although when I got it in 2004 I thought it would be good for a laptop, but then that just never happened either.))

Maybe one day someone who knows Nokia well might be able to say whether their phones can take a craggy AC wave.

david
 

Geniescience

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ok, got it.

The inverter hopping back and forth from positive to negative is what you are talking about, and that is what i figured.

When you asked it to me, i thought it had something to do with my short statement about transformers keeping a current's wave pattern.

Later, it looks like the other meaning of reverse polarity got picked up, i.e. two reversed-polarity AC waves. Also not relevant now.

David
 

snafflekid

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A Nokia battery charger should be able to handle the crappiest waveforms you throw at it. The voltage is rectified and filtered then chopped again to achieve DC.
 

Abikerboy

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jimbo said:
An inverter takes the car's DC battery voltage and outputs an AC waveform. Most commonly sold inverters take the 12VDC and output 120VAC. We should stop talking about polarity with an AC wave because it is not relevant.

Your charging cube for the phone takes a regular household 120 VAC and makes a much lower voltage, DC, to charge the battery. Why would you start with a car battery, invert it up to 120 AC, then "wall mart" it back to low voltage DC???? Why not just plug the phone in directly with a car adapter?
AC relevance is very important...no gimmick here!!!! Early inverters relied on the "chopped" dc waveforms simply because the designers knew no better!!! READ YOUR INSTRUCTIONS for connecting early ac electronic "frequency sensative" devices! DUHHHHHHH!!!! A simple cell charger is a ac "frequency sensative" device! Yep...I'll admit to being a dummy when it comes to certain devices! Fried a "electronically" ballasted flourescent lamp in my camper with this inverter, yet magnetic ballasts survived!!! EARLY INVERTERS CHOPPED THE DC VOLTAGE AT A RATE OF 60 CYCLES PER SECOND....meaning the voltage was pullsed and blocked 60 TIMES A SECOND, thasnks to the diode and the SCR regulator!!!!! Newer inverters, as im told, REVERSE THIS CURRENT AT 60 CYLES PER SECOND, (yep...appears your right jadnusha) and even the newest devices do filter and round the wave....NOWHERE NEAR THE SAME!!!! Take an analog volt meter into the output of an older inverter...the neddle will vibrate towards the apositive READING....REVERSE THE LEADS, IT WILL VIBRATE TOWARDS THE ZERO, OR NEGATIVE SIDE!!! HOOK IT TO AC< AND IT WILL VIBRATE OR CYCLE IN BOTH DIRECTIONS EQUALLY!!! Explain this to me if "positive/negative doesnt matter with an inverter!!!! Tried this test today before even challenging this responce!!! Put the same analog meter into an ac outlet...meter set on dc...if your lucky, youll question the reading. Not lucky? Then buy a new meter!!! Smart enough to use an osscilliscope? Then you understand when u see the waveform!!! Not that smart? Back away, cause I WILL TELL YOU what I would connect to my own body, and what I would walk away from! If I die...my stupidity...not yours!!!
 

Alternety

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The quality of inverter output varies significantly by price. Crappy ones give a series of stepped square waves with discrete increases in voltage until they get about where they are going and them back down. Lots of things hate this. Waveforms and voltmeter results would vary quite a bit.

A high end inverter can be found in solar systems and uninterpretable power supplies (not all of them are good). They can put out a pure sine wave as good as the outlet in your lining room. There is more than one way to do this but they essentially make the switching steps so small they become indistinguishable from a sine wave. If you look at one of these you would not see the funny results you get from a cheap one.

The ones made for use in cars used to use a "vibrator" (clean your minds up out there) which was just a buzzer with contacts driving a transformer. They were real bad. As noted in the post above above, some inverters just sort of replaced the buzzer with a solid state device.
 

Abikerboy

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alternety said:
The ones made for use in cars used to use a "vibrator" (clean your minds up out there) which was just a buzzer with contacts driving a transformer. They were real bad. As noted in the post above above, some inverters just sort of replaced the buzzer with a solid state device.
Sorry guys...lol...I didnt mean the "DUHHH" in the earlier post above in a smart cocky way...after reading back, just sounded rude. It was really my duh (long story)... My appologies. It wasnt meant the way it read..
 
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