I never replied to this thread until I was asked.
The EBay user could have easily typed "DC". Maybe they read this thread.
This ad just randomly came to me in an email. Thought i would be kind enough to share it with those who are stuck on thinking this is my evil plot to take over the electrical world or something.
I just shared a link that shows i didnt coin the term. Its not new, and Im not the only one that uses it. No reply was needed really.
PM Railfan
I think its just an honest misunderstanding.
greg - Philadelphia & Reading / Reading
rrinker Where's that dead horse when you need it? An analog signal can be carried with DC or AC. A digital signal can be carried with AC or DC.
Where's that dead horse when you need it?
An analog signal can be carried with DC or AC.
A digital signal can be carried with AC or DC.
Rich
Alton Junction
DCC is digital, DC model railroad power is not. If it's not digital, it must be analog, but a more correct way to state it would be analog <comma> DC. It's not a DCC loco, it's a DC loco. It's not a digital loco (which is sort of a Maerklin trademark), it's an analog loco. Analog DC sort of doesn't make sense and outside of train forums like this I can't say I've ever heard it or saw it stated that way in any of my engineering textbooks.
<grabs bat...>
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
PM Railfanhttps://www.google.com/?gws_rd=ssl#q=analog+dc The rest you can do on your own.
The rest you can do on your own.
I see several listings (5 out of 9) for a vintage clothing boutique called "Analog" in Washington, "DC"
some listings for an analog input (any value between 0 - 5V) vesus a digital (binary) input (such as TTL logic)
a listing from "Analog" Devices, a manufacturer of semiconductors
and images of DC devices with analog versus digital displays.
it doesn't look like "analog DC" is a very dominate electrical term, one that is used in engineering texts, and if used describes a particular product.
PM Railfan Ed, https://www.google.com/?gws_rd=ssl#q=analog+dc The rest you can do on your own. PM Railfan
Ed,
https://www.google.com/?gws_rd=ssl#q=analog+dc
THAT does not prove your point. You asserted the term has been around a long time. SHOW me. Cite examples. What pages on what book did Thomas Edison use it.
If you can't do that, you've got nothing.
Can you?
And telling me that I can do the "rest" on my own is like telling me to prove your point for you. That's not my job; it's yours.
Ed
NP 2626 "Northern Pacific, really terrific"
Northern Pacific Railway Historical Association: http://www.nprha.org/
Much ado about nothing.
There are only two forms of electrical current: direct (DC) and alternating (AC).
PM Railfan "Analog DC" IS a common description of DC power. Its been around since DC has been around.
"Analog DC" IS a common description of DC power.
Its been around since DC has been around.
Show me.
Wasnt looking for this specifically, but as I stated before.... "Analog DC" IS a common description of DC power.
I came across this in my emails. Figured i would share it.
http://www.ebay.com/itm/Bachmann-HO-Scale-Train-Analog-2-6-0-Steam-Loco-Pennsylvania-/191560387511?category=0&buyerid=ES9nPwr1PsWH0ENtQa0R6A==&emailtemplateid=92052980&sellerid=FpRekKD1aqAs7FCq0jRj5Q==&refid=store&ssPageName=ADME:B:SEMK:US:LISTG
(I have no affiliation with the EBay seller, never met them, nor talked to them).
I didnt coin the term, nor make it up. Its been around since DC has been around.
Maxman, not having a clue about what MZL stood for, I could make no contribution to your question. I was not ignoring it, I simple had never heard of MZL.
maxman tomikawaTT To answer a question that was asked, and then ignored: MZL Chuck, thank you.
tomikawaTT To answer a question that was asked, and then ignored: MZL
Chuck, thank you.
Maxman,
Your question was not ignored, I simply had not seen it yet.
And when I tested Google regarding MZL, I used no other descriptor - just the acronym.
Sheldon
tomikawaTTTo answer a question that was asked, and then ignored: MZL
To answer a question that was asked, and then ignored:
MZL - as originally envisaged and implemented by Ed Ravenscroft:
The key feature of MZL control is that electrical sections which would be separate blocks in traditional cab control are end-connected by contacts on the devices that move switch points. A train moving through something as complex as the throat of Grand Central Terminal needs power to only one section of track, probably the platform track at which it originates or terminates. The contacts that move with the switch points take care of the rest of the route.
I will admit that a knowledge of Boolean algebra is handy for designing the circuitry...
As for the Analog in Analog DC - pure DC has a continuous, constant voltage and polarity (as from a lead-acid battery, 2.2 volts.) We vary the voltage and sometimes reverse the polarity to control our miniature locomotives. Hence, the controls we use are an analog of the controls on a 1:1 scale locomotive...
I rest my case.
Chuck (Modeling Central Japan in September, 1964 - analog DC, MZL)
Because no one of these wonderful standards bodies that exists for just about everything ever made a standard for TLAs. Across diciplines, the same acronym means different things. In engineering, ADC is analog digital converter. It could also be the Art Directors Club in advertising, or the Association of Diving Contractors
My point is, AC and DC are types of current. Analog and Digital are types of signals. This back and forth about "well if there is analog direct current, there must be digital direct current" is completely meaningless because the two sets of descriptors do not go together. That's it. We've now had 3 pages of an pseudo-acronym that is not commonly if ever seen in the discipline to which it is being applied.
Wow, Randy, you mean acronyms may have multiple meanings? How can that be?
The problem is in combining two things that aren't really related. AC and DC are two forms of current (or an Aussie band). Analog and Digital are two types of signaling. Selection of current type does not preclude selection of signalling system. Most computers are digital, and happen to use DC current, however there's nothing stopping you from doing digital signalling with AC. There are also analog computers that use, well, analog signalling. Nothing says you can't use AC current in an analog computer, or DC current.
Likewise - we have analog control systems that in some manner vary the voltage that appears to the loco motors. We have digital control systems that send a digital signal to a decoder that controls the voltage that appears to the loco motor. You could have 60hz standard sine wave AC on the rails and still transmit a digital signal over that. You cna have fixed DC to the rails and transmit a digital signal over that - that's how many of the earlier comand control systems worked. You can have varying AC voltage on the rails to control trains - Lionel anyone?
In a nutshell analog does not always mean DC, digital does not always mean DC, digital does not always mean DCC, but DCC is always digital. ANd DC does not always mean analog.
PM Railfangregc what confuses me (as well as others based on the length of this thread) when I read something like analog DC is that it implies a difference between just DC and that there is non-analog DC? I bet it would really bake your noodle to think of AC as only being alternating DC!
what confuses me (as well as others based on the length of this thread) when I read something like analog DC is that it implies a difference between just DC and that there is non-analog DC?
I bet it would really bake your noodle to think of AC as only being alternating DC!
don't understand why you would think this.
But it makes the point I tried to make, which is if there is a term, Direct Current (DC), is there something that is not direct. Indeed there is, Alternating Current (AC). Alternating Direct Current (ADC) doesn't make sense.
but these are just one way of classifying electrical signals. Analog and digital are another way.
PM RailfanThus why the word "analog" is used. So you dont have to drag out a scope to see the difference in signals.
There are hundreds of ways to describe electrical signals. We don't say PWM DC and I've never seen signals for communication (e.g. FSK, PSK, QPSK, OFDM, CDMA, ...) which are almost always AC described as something AC (e.g. CDMA AC).
If you have the background, the differences between these signals can be describe precisely.
PM RailfanAnalog simply inferes pure, unchanged, unadulterated DC power. Straight off the source.
I disagree. Almost all modulated waveforms (radio and communication) are considered analog even if they are carrying digital data.
But if i understand your point in the context of a model railroad throttle, I think your trying to say that a DC throttle which simply controls a constant voltage on the rails should be described as analog DC
and a more advanced throttle that injects pulses or use PWM could not be described as an analog DC throttle, which I disagree with.
PM RailfanPWM IS a 'digital' DC signal. It IS a different signal from 'analog' DC and can be measured and seen on a scope. PWM has been manipulated to produce the pulse and the width.
I understand why you think it is digital. And based on your description of analog DC signals as having a relatively constant voltage, I can see why you think PWM can't be analog. But I wouldn't consider PWM as digital just because it has two states.
PWM is simply a different type of analog signal that is driving a purely analog device, in our case a motor.
PM RailfanPWM has been manipulated to produce the pulse and the width. DC is now NOT in its original, raw state (Analog!). That is what the word 'modulated' means - to change the signal (why call it pwm if its just DC?).
If the current flow in the signal does not change direction, no matter how complicated the voltage changes, it is not AC and therefore DC.
while PWM can be DC (i.e. on/off vs V+/V-), DC is only one characteristic of a PWM signal
PM RailfanIf DC is just DC no matter its form, then why was PWM and DCC coined as terms when we all could just be saying DC?
DC only describes one small aspect of the signal.
The DCC signal carrying both power and communications over the rails is AC. But that is only one characteristic.
Is DCC PWM? It uses PWM to control the motor voltage, but PWM doesn't describe the control part of DCC
Is DCC digital? it uses a digital processor.
PM RailfanWhat makes ADC redundant is the majority of the world only thinks in AC or DC.
I doubt this is true.
PM RailfanHeck from now on i will just say DC and let the reader wonder what type.
there is a large vocabulary of terms used to describe electrical signals which can be used to avoid confusion. There's no need to make up new ones.
While DC and AC mean direct and alternating current, in model railroading they tend to refer to the type of throttle. It would make sense to me to describe a digital DC throttle as using digital technology to control the analog voltage on the rails to a DC locomotive, just as describing a more common DC throttle using analog control circuits as an analog DC throttle.
Direct Current is what you get from a cell (or several, which is a battery.)
Alternating Current is created by a rotating machine.
DC can be created artificially from an AC sinewave.
A series of binary pulses is not Direct or Alternating Current. It is a pulse train, created by switching the signal state as needed.
Both AC and DC are used for analog control, by varying the voltage and current to change speeds, brightness, or whatever.
Analog DC is almost as silly as Digital Speakers or Headphones. Speakers are analog transducers, they don't work well (or last long) on a digital waveform. Just because some some audio equipment uses Class D or worse amplifiers to achieve high power outputs cheaply doesn't mean it is a digital signal either.
Put it to you this way, if there wasnt a difference in DC power (analog vs digital) then the screen infront of you would be an etch-a-sketch instead of a nice monitor! There IS a difference.
gregc what confuses me (as well as others based on the length of this thread) when I read something like analog DC is that it implies a difference between just DC and that there is non-analog DC?
I would think there is. Computers all day long use digital (non analog) DC signals both as power and control and certainly data transmission which is nothing more than massively complex streams of power itself. There IS a difference. PWM IS a 'digital' DC signal. It IS a different signal from 'analog' DC and can be measured and seen on a scope. PWM has been manipulated to produce the pulse and the width. DC is now NOT in its original, raw state (Analog!). That is what the word 'modulated' means - to change the signal (why call it pwm if its just DC?). Thus why the word "analog" is used. So you dont have to drag out a scope to see the difference in signals. Analog simply inferes pure, unchanged, unadulterated DC power. Straight off the source. PWM DOES NOT come straight off the source. The analog DC power has to be 'changed' before it can be called PWM. Now you see the difference.
What makes ADC redundant is the majority of the world only thinks in AC or DC. Thats it. Who ever really worries about the power coming out of the wall when they plug in a lamp or vacumm cleaner? But as you see, there are many forms of DC. ADC refers to its natural, raw state, in a distinct pattern (wave form). Thats it. Only meant to be a distinquishing aspect amongst the other related DC terms.
If DC is just DC no matter its form, then why was PWM and DCC coined as terms when we all could just be saying DC? Analog, however redundant, is no different in meaning as a term. It just describes DC in a particular form. This is what i was taught. Has served me fine for years and never have i ever seen it questioned like in this thread.
Heck from now on i will just say DC and let the reader wonder what type.
ATLANTIC CENTRALgregc PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE? You tell me?
PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE?
PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world.
is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE?
You tell me?
yes it is redundant in the contexts that I can find on these pages going back to 2009 (see tomikawa TT) where "good old analog DC" is being used to emphasis its difference from DCC.
ATLANTIC CENTRALThe Aristo Craft Train Engineer wireless radio throttles I use have a square wave full voltage pulse width modulated motor control output - would you call that digital?
I wouldn't, because a digital circuit does not depend on the actual voltage, simply its state.
In a motor circuit, its not just that the PWM signal is on for 50%, but that it is on at a specific voltage for 50% of the time to provide the equivalent of a constant voltage of some value.
The control portion of a PWM circuit could be analog or digital. It could be a discrete digital circuit or a digital processor (typical DCC decoder).
If you think of digital as simply having two states, would you describe a light switch in your house as digital?
Model railroads have had AC throttles and DC throttles. Now is has DCC which puts an AC signal on the track. But you wouldn't compare a DCC throttle to an AC throttle. It's not that simple.
Well, poking around the internet, it seems we have DC and AC, direct and alternating current. We also have analog and digital signals. According to http://www.researchgate.net/post/Is_DC_an_analog_signal, "if a circuit is using unidirectional (this means DC), non-time encoded current to communicate the value of a transducer, then YES - in this case it is acting as an Analog signal".
It also states "If a circuit is using unidirectional, non-time encoded current for reasons other than communication (such as providing power), then NO - it is not a signal, analog or digital." Based on these statements, it is my opinion that since we use DC to provide power, it is not a signal. Therefore analog DC is incorrect terminology in our application.
Certainly anyone who creates something can use any acronym he wishes. This does not mean that we should use non-applicable acronyms. Unless, of course, the goal is to either cause confusion or to be contrary, in which case one can do what one pleases.
Google is not "clueless" concerning MZL. I typed "MZL model railroad control" in the Google search box and got at least 10 refrences containing something about MZL, including http://www.dccwiki.com/DCC_History#MZL,
http://model-railroad-hobbyist.com/node/16475,
and http://model-railroad-hobbyist.com/node/7386
There does seem to be a conflict about what MZL actually stands for. One of the sources says "Master, Zone Layout", and the other says "Main, Zone, Local". So I'd appreciate it if someone could clear that up.
gregc PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. is analog DC redundant? Is there some other form of DC that is not analog, maybe digital DC? What exactly would that be? Did I miss something when I got my EE?
You tell me? The Aristo Craft Train Engineer wireless radio throttles I use have a square wave full voltage pulse width modulated motor control output - would you call that digital?
As opposed to most variable voltage/variable current DC throttles?
All acronyms are made up by someone - My control system is partly based on one called MZL by its creator, Ed Ravenscroft - easily read about in the back issues of Model Railroader right here on this site - but Bing and Google are clueless......
PM Railfan99% of us are model railroaders, not electricians. Ask an electrician what DCC is and he will be scratching his head. And before DCC ever became DCC.... what did you call it? You didnt call it anything because it didnt exist.
Before DCC was standardized and branded, I believe it was known simply as 'command control' and was AC powered on model railroads like the legendary V&O. The decoders were so big they had to ride in the tender or in a dummy unit.
All of the model railroaders I know are either electricians including myself or else A/V or IT geeks who think they are electricians.
PM Railfan In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. I spose since google is around now we can junk the old addage.... "experience wrote the book, not the other way around". Think of all the money that will be saved when google replaces teachers, since google knows everything. Cant wait to see if google will wire my layout for me. I will go ask it right now.
In glad google has been around as long as electricity has. And is the end all-be all of definitions in this world. I spose since google is around now we can junk the old addage.... "experience wrote the book, not the other way around".
Think of all the money that will be saved when google replaces teachers, since google knows everything. Cant wait to see if google will wire my layout for me. I will go ask it right now.
PM RailfanIn glad google has been around as long as electricity has. And is the end all-be all of definitions in this world.