First of all, sorry to the community - one should not be posting such a simple question (there is a google for that) but, after spending hours on the web, I just could not find a simple response about the naming conversions. Most of the search results go into a long history discussions of how these different names came about (PNP, etc) but did not help me much.
I am relatively new to the electronics and trying to figure out how to read circuit diagrams. Here are the basic assumptions:
There are positive and negative terminals (Cathode and Anode) and the term "negative terminal" is interchangeable with ground
Power sources could be separate for 1) logic circuit (side usually operating at 5V and where ICs reside) and 2) "power side" (not sure what to call this side) that may operate at a higher voltage and may include motor, etc.
Basic Eduino diagrams usually refer to Vs as a positive terminal and ground as a negative terminal. So, here are few questions I am struggling with (especially as I am trying to figure out this diagram):
Is Vs always a positive terminal and is there a distinction when it is for "logic circuit" (powering Arduino) vs. the "other side" (powering a motor)?
Vcc, Vdd is the same as Vs? I know there are historical differences (see here) but for practical purposes for a beginner are they the same?
What about Vd and Vc? These two were the most challenging to find the answer to. (The Instructable's diagram has Vc right after the R3 and at pin 5)
V(in) and V(out) - are these specific to input and output to an IC? for example, NE555's PWM output is V(out) and V(in) would be signal that IC receives (as opposed to Vs that powers the IC)? Are there other conventions or uses for these?
Name your supply net something specific like "5V" or "12V Batt".
Stop worrying.
The datasheet must use those funny names because it doesn't know what supply you have. It can tell you that Vcc must be between 3V and 12V but it doesn't know that you plan to use 3.3V.
the term "negative terminal" is interchangeable with ground
No. It can be but not always. Sometimes you have a split supply with a Positive - Ground - Negative
Basic Eduino diagrams
I assume you meant to type Arduino here.
especially as I am trying to figure out this diagram
Instructables are crap, do not read them unless you can spot errors. Never use them to try and learn anything, most of them have errors in them.
Is Vs always a positive terminal
Yes.
is there a distinction when it is for "logic circuit"
No.
Vcc, Vdd is the same as Vs?
No not always but they can be.
Vee, Vss and ground are the same?
No. Never seen Vee on a diagram in 50 years of looking.
What about Vd and Vc? These two were the most challenging to find the answer to. (The Instructable's diagram has Vc right after the R3 and at pin 5)
As I said instructables are crap, in this case Vc means the voltage across the capacitor, but could mean the voltage on a collector or anything else beginning with C.
V(in) and V(out) - are these specific to input and output to an IC?
Not restricted to an IC it can refer to anything, like a sub system or amplifier.
Grumpy_Mike:
Instructables are crap, do not read them unless you can spot errors. Never use them to try and learn anything, most of them have errors in them.
No. Never seen Vee on a diagram in 50 years of looking.
Thank you, all for your responses. I guess there are no straightforward answers for these. Will keep digging; it is tons of fun except when I cannot figure it out - which is most of the time.
Various industries have their own conventions. ie, where I worked "ground" was normally called common or com simply because it might or might not be connected to the ground. Com was then split up into Acom, Dcom, Pcom for analog, digital, and peripheral common. They would usually all make their way to the ground connection at one point. Sounds a bit arbitrary but it was all done in the interest of electrical noise control and I think it helped.