OT: Numitron clocks for sale.

Ethan Dicks wrote: My understanding of the history is that RCA originally produced a single-envelope incandescent 7-segment display device they called the "Numitron" around 1969/70 (RCA Part #: DR2000), in a vacuum-tube style envelope with a standard 9-pin miniature-tube base. The Numitron is described and shown in the book "RCA Solid-State Hobby Circuits Manual" (Printed Sep 1970). (The book includes several circuits, such as a clock, utilising them. Most of the circuitry is discrete transistor logic, except for the use of an early 7-seg decoder-driver IC, the CD2500E.) The Numitron is referred to as being "recently developed". Other phrasing leads one to believe that "Numitron" was an RCA trademark. I suspect the name went the way of "Kleenex" and came to be applied more generally as other manuacturers produced similar devices or copies. I believe the more-prevalent 7-seg incandescent displays in a rectangular-envelope form factor (with DIP-IC pins to fit in standard IC sockets) followed shortly thereafter from other manufacturers. These are often referred to as "Minitrons", although, again, I believe that was actually one manufacturer's tradename. There are variations in size and pinout between different manufacturers in this style as well.