According to clarence at snyder dot on dot ca:
On 26 Sep 2007 21:14:28 GMT, (DoN. Nichols)
wrote:

[ ... ]

Well ... something else to *add*. The typical automotive
vibrator ran somewhere near 60 Hz (since there were lots of 60Hz
transformers around), but I had (and may still have somewhere) a special
vibrator and matching transformer which had the reed weighted to lower
the frequency to 20 Hz, and it was used to generate the ring signal for
small telephone exchanges -- from before the Sub-Cycle passive devices
to do the same thing by dividing the 60 Hz power line frequency by
three. (I never have been able to find out exactly how they did that,
but I have two sealed units of that type -- different load capacities.

Enjoy,
DoN.
I remember the vibrators being something like 255 hz. High frequency
is easier to filter, and works just fine on lower frequency
transformers.

O.K. I can accept that. I never bothered to check the
frequency (I didn't have a way to do so back when I had normal
vibrators. :-)

Enjoy,
DoN.
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