EEVblog Electronics Community Forum

Electronics => Beginners => Topic started by: Aethelstan on February 10, 2018, 04:08:34 pm

Title: A question of gain notation.
Post by: Aethelstan on February 10, 2018, 04:08:34 pm

Hello, up front I must state this question does relate to an assignment I am working on. I am converting gain for op amps between arithmetical and dB, and I understand the maths but I am a little confused regarding the actual notation for the two scales. If I have a gain of 20dB, is that simply G=20dB, or do I use the unit for power gain of G_P? If I use that, do I use the notation of G_V for arithmetical gain? Or, should I simply use G and the unit of dB or unit-less V/V signifies which type of gain I am talking about?

Thanks :)

Title: Re: A question of gain notation.
Post by: CatalinaWOW on February 10, 2018, 04:39:09 pm

In my experience there are no robust conventions for this.  It would save some trouble if there were.  In documentation I generate I explicitly define the notation I use.  In documentation I am reading I am very cautious about assuming usage, and often have to run a series of calculations to figure out the authors usage.

If your professor has not expressed a strong preference just document what you do.  (Run through some test cases to make sure you are self consistent.)

Title: Re: A question of gain notation.
Post by: tggzzz on February 10, 2018, 04:48:07 pm

I would use "gain of 10" or "gain of 20dB". If I thought it might be ambiguous or might clarify a point, I might use "voltage gain of 10" or "gain of 10V/V".

Title: Re: A question of gain notation.
Post by: Zero999 on February 10, 2018, 04:58:34 pm

I've always used A_V for voltage gain and just A for power gain.

In any case, it should be fairly obvious whether voltage or power is being discussed, by the context.