Correction on the last formula:

Voltage ratio:  20 * log_sub_base10 (V1/V2) = dB



----- Original Message -----
From: Jim P <jvpoll@dallas.net>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Saturday, May 27, 2000 1:36 PM
Subject: Re: [PIC]: Audio Ideas?


Oops! Did anyone else catch this?

"of the converted result to drive one of the LED's (each
 LED would then represent a factor of 2 (I think that is 3 dB!)."

- S/B  "6" dB

(Not meaning to beat a dead horse or anything - but here's
  a quick review of the dB anyway ...)

Voltage factor of         2 = 6 dB
Voltage factor of  1.414 = 3 dB

Power ratio of 2 = 3 dB
Power ratio of 4 = 6 dB

Computing decibels:
Power ratio:    10 * log_sub_base10 (P1/P2) = dB
Voltage ratio:  20 * log_sub_base10 (P1/P2) = dB