[sdiy] Zero gain, unity gain, was: RC filter questions + SPICE RC filter simulation questions

[Ingo Debus]

Am 18.04.2010 um 02:11 schrieb Neil Johnson:

> Ingo Debus wrote:
>>> "The unusual RC circuit on the rear cover gives a maximum voltage  
>>> gain of just over 15%. Ordinary RC circuits give less than unity  
>>> voltage gain. "
>>
>> I'm lost here. Isn't a voltage gain of 15%, or 0.15, clearly lower  
>> than unity?
>>
>> Or does he mean 1.15? This would be 115%, no?
>
> A *GAIN* of 15%, or put another way 15% above 1.0, or put another  
> way 1.15.

So gain is defined as what is gained with respect to unity gain?
In other words, unity gain is no gain? ;-)

Well even The Art Of Electronics uses the term gain loosely. In their  
chapter on operational amplifiers voltage gain is defined as Vout/Vin  
(p. 178). But explaining the emitter follower they say "it has no  
voltage gain" (p. 65).

Ingo