[R-1051] +4 volts

[Ray Fantini]

+4 volts, and +3 were a common voltage to use when building early transistor divider (MMV) chains. Years ago I worked on lots of television timing equipment built by a company called Riker Video that's was an early adapter of transistor technology and those dam things were loaded with germanium divide by two , three and ten circuits and the whole mess was powered by +4 volts.  Think low voltage was standard for building logic circuits before the integrated circuits.
When I started in electronics TTL and CMOS were king, LSI was just starting, except for a short period of time working on the Riker junk have little or no experience with the earlier DTL or RTL stuff. Looking at a lot of the early guidance and INS navigation stuff there was a lot of earlier integrated devices out there, what happened to all that stuff? The later 1051 and URC/URT are about the only examples you can find of mid to late sixties technology.
Ray F