# Audio Frequency Amp

#### celect

Joined May 31, 2005
18
How do I determine the input signal power if the over all gain = 40db and the out put signal level = 6 watts.

#### beenthere

Joined Apr 20, 2004
15,819
Hi,

If I'm correct, you can look at the dB scale numbers as exponents. That would mean your gain is four orders of magnitude (10 to the 4.0 power). If that is the power gain, divide your 6 watts by 10,000 and there you are.

#### n9xv

Joined Jan 18, 2005
329
Gain factor = 10 raised to the exponent (dB-gain / 10)

So,

10^(40/10) = 10^4 = 10,000

Therefor,

Input power = 6/10,000 = .0006 or 600-uW (microwatts)

#### davidand

Joined Jun 2, 2005
43
Originally posted by beenthere@Jun 2 2005, 09:13 PM
Hi,

If I'm correct, you can look at the dB scale numbers as exponents. That would mean your gain is four orders of magnitude (10 to the 4.0 power). If that is the power gain, divide your 6 watts by 10,000 and there you are.
[post=8175]Quoted post[/post]​

thanks for info, I now understand the text.