Charles Petzold diagram confusion

[adam2016]

This may belong in the lounge but it is related to programming all be it at a much lower level.

In Charles Petzold's Code, the diagram leaves a lot of ambiguity, it describes two telegraph stations and the communication between them

here is the diagram - https://ibb.co/WkVbymN

he says that the V symbol replaces a battery with the negative terminal connected to ground, so do we have 4 grounds in this diagram?

more importantly which points are connected to each other? are the two ground symbols connected? are the 2 V's connected?

why is one winding in the box?

and finally why is there no clicker on our friends telegraph station?

Thanks

[dutch]

Your questions suggest that you need to go back and reread the chapter, carefully.
BTW, "all be it" is usually spelled "albeit".

(If any regular needs a copy of this book, PM me.)

[adam2016]

albeit is correct but my browser was throwing up a spelling mistake for albeit, so I just changed it to all be it to "keep the beast happy",

but I think we're getting off topic, this isn't a thread on grammar and spelling. I've read the chapter a few times and still can't figure it out, seems pretty ambiguous to me.

Could you perhaps give me a hint?

[ne555]

> This may belong in the lounge but it is related to programming
... pure noise

General C++ Programming
Anything about programming in C++

[adam2016]

> This may belong in the lounge but it is related to programming
... pure noise
General C++ Programming
Anything about programming in C++

Well technically it's loosely related to C++ programming, without electronics and circuitry we wouldn't be able to program in C++...

but I digress, if there was a way to move it to the lounge I would but the only way I could imagine that being possible would be for an admin to move it and since we all know they very irregularly frequent the forum that would be a lost cause. I could make another post in the lounge but that would be double posting.

With all that being said. Care to give me some hints?

Thanks

[mbozzi]

"V" denotes a source of positive voltage, relative to ground.

are the two ground symbols connected?

All grounds are connected.

[Ganado]

Ground just means "0 voltage [relative to whatever else]". If it helps your mental model to connect them, go ahead. (But even if they were connected, no current would travel between two places with the same voltage.)

[adam2016]

Thanks mbozzi,

I think I'm probably misinterpreting the "V", are the "V"s connected to one another?

[dutch]

All connections are shown.
Of course the separate voltage sources are not connected.
That's the whole point of the relay.
It is electrically isolated from the circuit on the left.
That's the topic of the section.
Which you of course read carefully.

[againtry]

This may belong in the lounge

Sure does

but it is related to programming

No it isn't

all be it at (sic) a much lower level.

It still doesn't however many times you say it.

this isn't a thread on grammar and spelling

This aspect does in fact have a very close relationship with programming

do we have 4 grounds in this diagram

No, there is only one ground with 2 connections to it, as shown. Petzold forgot to show how the voltage sources are connected but covers it by the highly technical term 'more or less' and your claim he says the batteries are connected to ground. Whatever, still one ground and now apparently 4 connections to it.

why is one winding in the box?

Probably to 'encapsulate' the concept of a relay with input and output and to diagrammatically 'hide' the inner workings.

why is there no clicker on our friends telegraph station?

There is!

BTW This book is rubbish.
(Try making the circuit yourself with a dry cell battery. Don't earth it because it won't work.)

[adam2016]

to be honest still not too sure of all the connection points :/

here is a snippet from the chapter before where he tells us to use the "V" symbol to replace a battery with the negative terminal connected to ground.

- https://ibb.co/Cn5wbZ8

He also shows us the one way lightbulb morse code system.

Assuming power flows from negative to positive and the switch is closed, I'm guessing current flows from the negative terminal of the V sign ( goes to ground ) then current comes out at "your friends house" and flows through the lightbulb and hence lighting the bulb and back to our battery assuming completing the circuit.

but knowing all that, the telegraph uses 4 different ground symbols right? two ground symbols for the V ( battery with negative terminal connected to ground ) and then 2 separate ground symbols - https://ibb.co/WkVbymN

so how do all these symbols connect? and how can we use 4 connections to the ground?

Thanks

[adam2016]

Ah Ok, I'm starting to understand now, I was missing a few points, the black box in the middle is the relay station

I drew the connection points and what is happening here, please tell me if this is correct (I think it is)

https://imgbb.com/

Our telegraph station initiates a message by pressing the clicker, the current flows from our station to the relay station and goes through the windling (this determines weather it is a dot or dash ) the current is then sent our connection point A and triggers B , the current then flows through wire B to our friends relay station where the message is received, the current then flows back out through the ground ( connection point C ) to our telegraph station ( connection point D) completing the circuit,

that makes sense, but why does Charles decide to draw the ground symbol for connection point A?? wouldn't it make more sense for A to be connected to B by just a wire considering they are at the same relay station?

[againtry]

An easy way to remove Petzolds bad explanation is simply to draw a picture with 2 batteries with both terminals connected without the ground. In other words exactly how you would do it with real batteries and no earth.

There are 2 battery circuits!

Each battery has a wire coming out of one terminal, connecting to the switch/relay, and then another wire going from the switch/relay going back into the other terminal of the battery.

Once you get that Petzold is just taking one wire in each circuit and connecting each end of it to earth which in effect as he laboriously explains is a hidden substitute of the removed wires.

[adam2016]

There are 2 battery circuits!

ahhhh yes!, that makes sense now

one circuit from A to D and one from C to B

yeah very poorly explained by the author (here at least), he left a lot to the imagination although I did overlook the electromagnetic facet of the chapter.

[helios]

Well technically it's loosely related to C++ programming, without electronics and circuitry we wouldn't be able to program in C++...

Are you serious? Should we discuss astrophysics too? After all, without stellar nucleosynthesis we wouldn't have silicon or copper.

Take this to the lounge, man.

[adam2016]

too late now Helios haha

I wish there was an option to move a thread to another section, would be a nice feature.

[Ganado]

Go to the top of this page.
On the left-hand side above your post, click "Edit Topic".
Click on the Forum dropdown menu, and select Lounge.
Click Submit.

[adam2016]

@Ganado oh nice, never knew that, exactly what I'll do

@Dutch now it makes sense, I think Petzold could have made it a little clearer though.