Pretty funny. As a ham radio operator I have had 4 clocks on the walls for years. I obtained 5 IBM clocks quite a while ago and built drivers and such for them. Actually ran them for a while but found the noise annoying. Replaced them with cheap wall clocks internal drivers removed and a master system that drives them. NOT connected to GPS since its really just a relative thing. Is it dark in the UK or Japan. This has been running about 10 years and I do correct the time at the DST switch and occasionally in between. But its a stable low power thing that runs for months on C cells if the mains go away. Regards Paul WB8TSL
On Sun, Nov 2, 2014 at 6:36 AM, Mitchell Janoff <[email protected]> wrote: > The rapid clicking of slave clocks in schools was a design feature of IBM > (and later Simplex) clocks. The master clock sent out minute pulses to the > slave clocks for the first 50 minutes of each hour on the "A" side of the > circuit. Slave clocks operating on-time would automatically switch to the > "B" side of the circuit and wait for the 51st minute pulse on the "B" side. > Slave clocks operating slowly would remain on the A side and receive pulses > at a rate of 1 every 2 seconds until they automatically switched to the "B" > side at 50 minutes past the hour. Slave clocks that were running fast > arrived at 50 minutes past the hour prior to the master and switched to the > "B" and waited for the next pulse on the "B" side at 51 minutes past the > hour. On the hour all the slave clocks switched back to receive the hour > pulse on the "A" side. This was all accomplished by a cam in each of the > slave clocks that moved a switch from the "A" side to the "B" side. For > power outages (the master clock coul > d continue to operate on a spring or weights but could not send out the > impulses), the master clock could be fitted with an optional accumulator > that counted the missed pulses. When power was restored, the accumulator > would "unwind", sending out rapid pulses until the slaves could catch up. > This could also be used to move the clocks ahead 23 hours (retard by 1 > hour), or ahead hour for daylight saving time. Therefore the > click-click-click in the classrooms as slow slave clocks caught up to the > master. > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
