In message <7c37.12cdef25.39a12...@aol.com>, ewkeh...@aol.com writes:
>I am not seeing it, what should I use to measure it 3561 and 70000 spec >analyzer do not show it? It is probably the 3561 not the 70k that has the best chance. I am not aware of the precise characteristics of the noise, but it sounds somewhat like a boiling pot. I became aware of it first time when I ran a small class-A audio amplifier from a couple of, probably too, small VRLA's some years ago, just for the fun of it. With no input signal, the speakers would gurgle faintly and it took me some time to locate the source of the noise to the batteries. I would guess its amplitude correlates with the ratio of discharge current to plate area, since it is chemical/mechanical in nature. These days, I would build a super-cap battery instead if I needed a low-power PSU with low noise. Poul-Henning PS: also be aware that almost all VRLA's have a very nasty resonance frequency somewhere in the low MHz band. If you are after low noise, you should always decouple the battery good poly/plastic caps right at the terminals. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.