DC Power supply question...duh...

From: Dave Dameron <ddameron_at_earthlink.net>
Date: Sat Jul 3 14:07:31 1999

At 11:28 AM 7/3/99 -0400, Allison wrote:
><Boy does that sound like spec. inflation! 24 p-p is just 12 Volt peak in
><either polarity with a bridge circuit. That gives 12/8 peak amps and 18
><peak watts (like with a +/-12 volt square wave). The RMS voltage and
>
>no that would be 24/4 (two speakers presuming they are parallel) or 6A.
>Assumes a 100% lossless bridge amp. at 24VPP and 6A you have 144W if it's
>a symetirc squarewave, less if sine(RMS).
>
Sorry, I cannot tell if you switched from an engineer to a marketroid ;).

In this bridge circuit with a 12 volt supply:

+12 -------
    A B
    .LOAD..
    C D
return-----

(A, B, C, D) are switches, either A, D or B, C on,
The 4 Ohm load sees a maximum current of 3 Amps in either direction.
That is 1.5 Amps for each of two 8 Ohm speakers in parallel.
The maximum (peak) power is 36 watts, 4x that of a non-bridged amplifier.
"peak to peak power" is just a marketroid term. Actually I don't even use
the term "RMS power", as IMHO, "RMS" applies to voltage or current, not power.
-Dave
Received on Sat Jul 03 1999 - 14:07:31 BST