RE: Relative Voltage Notations

Thread Starter

SamR

Joined Mar 19, 2019
5,052
Relative Voltages can be expressed in various ways. Vab = 100V, Vab =+100V, Vab = 100V +ve

What the heck does this ve stand for? Voltage to Earth?
 

ronsimpson

Joined Oct 7, 2019
3,042
I encourage people to wright all over the schematic. More information is better.
Maybe Ve is emitter voltage. or Maybe Va, Vb, Vc and Ve are all supplies. I like V100, V50, V35, V5micro which is not the same as V5isolated.
 

Thread Starter

SamR

Joined Mar 19, 2019
5,052
Nope, not emitter V. Used in simple circuit analysis to denote relative voltage between Point A and Point B. I know I've seen it before but no idea what it actually stands for?
 

Thread Starter

SamR

Joined Mar 19, 2019
5,052
The book does state that the + is assumed unless the - is actually used to denote negative. So it could be ve & -ve. Anyway, sounds like a plausible explanation, thanks!
 

MisterBill2

Joined Jan 23, 2018
18,566
Here is a guess, which is that Ve is short for Voltage to earth. And the lazy author naturally did not include their personal acronym because they assumed "everybody knows it." I never came across that in my career, or in any class.
 

WBahn

Joined Mar 31, 2012
30,071
Relative Voltages can be expressed in various ways. Vab = 100V, Vab =+100V, Vab = 100V +ve

What the heck does this ve stand for? Voltage to Earth?
+ve is shorthand for positive (and -ve is shorthand for negative).

I've never seen either used in that way, however, and I think it is very poor notation.
 

WBahn

Joined Mar 31, 2012
30,071
The book does state that the + is assumed unless the - is actually used to denote negative. So it could be ve & -ve. Anyway, sounds like a plausible explanation, thanks!
That is referring to a value that lacks either a positive or negative sign.

So 100 V is understood to mean +100 V, while if you mean a negative 100 V, you need to explicitly use the negative sign and write it as -100 V.

It does NOT refer to leaving the + off the shorthand +ve.

These shorthand notations are used in text, not with actual numbers. For instance, something like

If the cathode is -ve relative to the anode, the diode is reverse-biased and virtually no current will flow. But if it is +ve, then the current flow through the diode will be exponentially related to that voltage.
 

MisterBill2

Joined Jan 23, 2018
18,566
Like I said, LAZY authors "shorthand notations are used in text" instead pf "positive" or "negative."
Of course I do admit to a prejudice against lazy.
If one is attempting to present information, spending the effort to present it clearly is the way to go. Clarifying acronyms at the start of a section is done by quite a few writers in some publications, while other authors evidently believe that their intended readers already know, and the others don't matter.
 

Thread Starter

SamR

Joined Mar 19, 2019
5,052
My experience goes back many decades and have often come across it.
The author is English so maybe it's an English thing? He also uses rectangles for resistor symboIs in the schematics. I want to say I've seen it before (my memory is getting worse) but only in passing. Never had to use it and probably still won't. Vab =100V or -100V is good enough for me and don't think I'd misunderstood using that form.
 

WBahn

Joined Mar 31, 2012
30,071
He also uses rectangles for resistor symboIs in the schematics.
This is actually quite common, both in some CAD systems, and also in hand-drawn schematics or, using general purpose drawing software such as Paint or PowerPoint. It's just a lot easier to draw a generic rectangle and let the value tell you if it's a resistor, inductor, or capacitor.
 

MisterBill2

Joined Jan 23, 2018
18,566
My older "RapiDesign" templates use the zigzag line for resistor while my newer templates use the rectangle. ZigZags are easier to draw when sketching, rectangles are easier when actually drafting.
 
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