Very much On Topic: Integrated Vacuum Tubes

William> RCA's Nuvistor - a family often found in late 1960s TV William> tuners and some test equipments. They are almost always William> triodes, and are really small - 3/4 inch long, maybe 3/8 William> inch diameter, all metal. RCA made a few half sized William> Nuvistors, but never sold them. I think acorn tubes are smaller. Those are UHF tubes -- I think they were used in 1940s or 1950s vintage equipment for oscillators or amplifiers up to a gigahertz or so. They look just like glass acorns, with stiff wires coming out the sides for connectors. The idea is to keep the wires very short, and also to allow them to be connected into resonant transmission line circuits where the pins are just part of the resonant line. paul