Wai-Sun Chia wrote: >Wow. That is sooo coool... >What other pseudo-SSI tubes exist/existed? I mean for higher-level >functions; e.g. adders, counters, flipflops, decoders,....(TTL >equivalents). > > Now if you want analog -- 1926 was good year. :) http://www.oldradioworld.de/3nf.htm