Proper Value Notation -- how to write VDC and VAC?

In summary, the discussion is about the appropriate notation for specifying DC and AC voltage excitation. While Vdc is commonly used for DC voltage, there is some confusion when it comes to AC voltage. It could be marked as Vac, Vrms, Vp, or Vpp, depending on the industry or software being used. There doesn't seem to be a specific standard for subscripts, so it's best to use what looks most appropriate at the time or adapt the idea of using clean signals vs measured components.
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EE4me
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TL;DR Summary
When specifying DC vs AC voltage excitation, is it appropriate to type 50 VDC with DC as a subscript? OR should it be "V DC"?
When specifying DC vs AC voltage excitation, is it appropriate to type 50 VDC with DC as a subscript? OR should it be "V DC"? The same concept if it were AC.
 
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Vdc is simple, but Vac often needs more than just AC.
Vac could be Vrms in the sinewave power distribution industry.
It could be Vp, in math or SPICE modelling software.
Or even Vpp, when measured on the screen of an oscilloscope.
 
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I don't know about any specific standard, but we tend to use VDC and VAC as a marking for supposedly 'clean' DC and AC sources, while VDC and VAC as measurements of the specific components of a 'mixed' source.

But, again, I think it's just kind of intuitive usage and I don't know about any actual standards regarding this.
 
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Tom.G said:
To add to the confusion, see: https://www.physicsforums.com/posts/3015351 from 12 years ago. (and for more confusion, there are a couple typing errors in it too!)
I was looking at the IEEE guideline and noticed they specifically state that DC and AC are not capitalized. I've seen both and capital looks better to me so I'll probably stick with that. I haven't seen subscripts addressed so I was wondering if there was any specific notation. Since there's doesn't seem to be a "standard notation", I guess I'll just go with what looks best at the time. Or maybe adapt your suggestion earlier about clean signals vs measured components :oldsmile:
 
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1. What is the difference between VDC and VAC?

VDC stands for "volts direct current" and refers to the measurement of electrical potential when the current flows in one direction. VAC stands for "volts alternating current" and refers to the measurement of electrical potential when the current alternates in direction.

2. How do I write VDC and VAC properly?

VDC and VAC should be written with a capital letter for "V" followed by lowercase letters "DC" or "AC" respectively. The unit of measurement, volts, should be written in lowercase letters.

3. Is there a specific format for writing VDC and VAC?

Yes, VDC and VAC should be written with a space between the value and the unit of measurement. For example, "12 VDC" or "120 VAC". It is also important to include the appropriate symbol for the unit of measurement (V) after the value.

4. Can I use other symbols or abbreviations for VDC and VAC?

No, it is important to use the standard symbols and abbreviations for VDC and VAC to ensure clear communication and consistency in scientific notation. Other symbols or abbreviations may cause confusion or misinterpretation.

5. Are there any other factors to consider when writing VDC and VAC?

Yes, it is important to also include the frequency of the current for VAC measurements. This can be written as "120 VAC, 60 Hz" to indicate a voltage of 120 volts and a frequency of 60 Hertz. Additionally, it is important to use the correct decimal point and significant figures when writing VDC and VAC values to ensure accuracy.

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