42 code

[poppo]

Show your waveform.

Pretty basic stuff. I built an inverter out of spare parts 20 years ago. DC in - AC out. No common ground so the amplified output is AC. The originating sqare wave would go from 0V to 12V (or whatever your input voltage is). Even if it did not go through a step up transformer for isolation, the sqare wave would still be 12V AC across the output (i.e. measured with a non grounded meter).

[brichter]

I'm disappointed you fell for that.


That's a voltage waveform. Before you can have a technical discussion about electricity, you need to understand the difference between voltage and current.

[reho33]

OK, but we have not pinned down the answer: Does spinning the reels when the machine is on ruin anything or not?

[brichter]

OK, but we have not pinned down the answer: Does spinning the reels when the machine is on ruin anything or not?

If I hook it up to the engine in my motorcycle and spin it at 13000 rpm, I can guarantee it will ruin something...

[Foster]

Is it normal for a reel being spun by hand with power applied to cause a Base Chip, Game Chip, Version Chip, SP or SS chip to fail no way.
Can it happen yeah but not very likely.

I think the Base chip just happened to fail either at the time the reels where moved by hand or afterwords.
Anything man made will fail or breakdown eventually.

[poppo]

I'm disappointed you fell for that.


That's a voltage waveform. Before you can have a technical discussion about electricity, you need to understand the difference between voltage and current.

I'm not going to get into an argument about this, but I was an electronics instructor in the military for many years. Voltage and current have a direct relationship. Simply put, if you put a load on the output you will be drawing current I=E/R. The amount of current of course will depend on the design. This is basic electronics.

Here is a very simple inverter design. The source is 12V DC. The Q1 & Q2 oscillate at a frequency depending upon the RC network used. The resulting waveform (more of a sine wave in this case) will vary between 0V and 12V. This gives you an AC voltage across the primary of T1. So even if you did not use the secondary winding, there is still an AC current flow through the primary. The transformer steps up the voltage (and reduces the current) and you now have 120V AC on the secondary. The same can be done using a square wave but depending on the frequency, the primary winding may overheat. Hence the use of modified sine waves in most common inverter designs.

[poppo]

And to simplify it even further, here is a simple square wave (pulsed DC) at 60Hz. Assuming a 12 ohm load is connected to this, during the rise time from 0v to 12V you will draw increasing current across the resistor until it peaks at 1 amp (I=E/R). During the fall time back to 0V that current will decrease to 0 amps. Hence you have alternating current (AC). The only difference between a square wave and a sine wave is the square wave has a faster rize time and will stay at it's peak current and zero current levels longer. Increase the square wave (pulse) frequency enough, and the difference becomes negligable (which is the basic concept used in a switcher power supply). 

alternating current (AC)
Flow of electric charge that reverses periodically, unlike direct current. It starts from zero, grows to a maximum, decreases to zero, reverses, reaches a maximum in the opposite direction, returns again to zero, and repeats the cycle indefinitely.

http://encyclopedia2.thefreedictionary.com/Alternating+Current
 
Can't make it any simpler than that.   

[brichter]

And to simplify it even further, here is a simple square wave (pulsed DC) at 60Hz. Assuming a 12 ohm load is connected to this, during the rise time from 0v to 12V you will draw increasing current across the resistor until it peaks at 1 amp (I=E/R). During the fall time back to 0V that current will decrease to 0 amps. Hence you have alternating current (AC). The only difference between a square wave and a sine wave is the square wave has a faster rize time and will stay at it's peak current and zero current levels longer. Increase the square wave (pulse) frequency enough, and the difference becomes negligable (which is the basic concept used in a switcher power supply). 

alternating current (AC)
Flow of electric charge that reverses periodically, unlike direct current. It starts from zero, grows to a maximum, decreases to zero, reverses, reaches a maximum in the opposite direction, returns again to zero, and repeats the cycle indefinitely.

http://encyclopedia2.thefreedictionary.com/Alternating+Current
 
Can't make it any simpler than that.   

Mark, you're right. You can't make it any simpler than that, and I see where you're making your error.  

The current flow must REVERSE, not simply drop to 0, in order to be alternating current. You state in your example that since current flow drops to 0 that the criteria for AC has been met, but it has not according to the definition you reference.

<edit>

Don't get caught up in thinking the waveform shape itself has anything to do with whether it is AC or not. Sine, square, modified sine, sawtooth, etc., matters not one bit, it is simply the direction of current flow that is the determining factor.

[Foster]

Are audio signals considered AC, yes

Then Ponder this: In the simplest AM radio they use a diode to detect the Audio portion.

I can guarantee that that audio is not crossing 0 but is still considered AC.

[poppo]

The current flow must REVERSE, not simply drop to 0, in order to be alternating current. You state in your example that since current flow drops to 0 that the criteria for AC has been met, but it has not according to the definition you reference.

 

It does reverse. If one were to take a 12V battery and generate a square wave (or sine wave), then you would indeed have AC measured across the output. This is the fundamental reason inverters work. All of the criteria has been met.

But here is proof. I set up my signal gen to produce a square wave with a zero volt reference. Put it on my scope and then measured the AC voltage across it with my Fluke (which has no common zero reference). Factoring RMS, it's right on the money. And even if it did have a common ground, it would still be AC. AC does not have to go below ground (zero) to be defined as alternating current. As long as the current rises and falls - by definition it is AC. If I would have put a resistor or inductor or whatever across those leads the current would indeed be reversing as far as the component is concerned. The 'zero' point would be 1/2 of whatever the peak to peak of the signal is.  

But this is getting way off topic and I'm not going to keep trying to explain basic electronics. I've been doing this for too long.

edit - Foster makes a good point. If I were to connect this signal to a speaker (which is current driven) it would hum along just fine as the coil would need AC to work.

[brichter]

Are audio signals considered AC, yes

Then Ponder this: In the simplest AM radio they use a diode to detect the Audio portion.

I can guarantee that that audio is not crossing 0 but is still considered AC.

Your mistake lies in the fact that you state audio waveforms are AC (which is correct), but it is not correct to state that ALL audio waveforms are AC.

Just so we're clear on this, take a look at
http://www.ece.cmu.edu/~ee321/spring00/lab3.pdf

Look at the waveform after the diode in Fig. 3.4, you'll plainly see that it is a DC waveform that is input to the earphone, and even though it is DC, it is perfectly capable of driving the earphone.

[poppo]

Your mistake lies in the fact that you state audio waveforms are AC (which is correct), but it is not correct to state that ALL audio waveforms are AC.

They have to be AC or the speaker coil would not work. You keep confusing ground reference for some reason as part of the criteria when it's not.   I could take that signal I showed above, stick two 100K ohm resistors in series across it and use the tie point as 'zero'. I would then have a signal going positive and negative in relationship to that point. That didn't make it any more or less AC then it started.

[knagl]

Anything man made will fail or breakdown eventually.

Except Twinkies.

[Foster]

You are