Being fair, this clock was designed a long long time ago when stuff directly connected to the mains was not so frowned upon - Mike is a professional engineer and his page is covered with notes recommending that isolation transformers are used - he readily admits that today, he would never design a clock like this.
There is pretty much no immunity from mains-borne noise in the circuit - if you have anything at all noisy on the same ring/whatever, your clock will run fast or the noise will cause all sorts of other exciting issues. The circuit absolutely must have 100n ceramics for each chip (standard practice anyway) instead of just the couple it uses, and the 5V supply is derived direct from the mains via a 4V7 zener/100uF, i.e. no noise filtering there either. The 50/60Hz mains input is current limited by 2Mohm and then the ESD protection of a 4013 used as a buffer is used to clean the signal a bit. Nuff said, really. Personally, I'd never recommend someone build this circuit - there are far better & safer ones out there. Nick -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/c9c1566f-0013-47e5-ba6b-27fe1fa96e89%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
