TRANSISTOR MUSEUM Historic Transistor Photo Gallery
Transistor Size (3/8” Diameter X 1/2” H) Date Code 505 (1955 Week 5) Packaging- None	RADIO RECEPTOR RR66 TYPE Germanium PNP Alloy Junction Photo Transistor USAGE Light Sensing and Switching DATE INTRODUCED 1954 CASE STYLES Silver Metal Base with Clear Glass Top AVAILABILITY Rare – Limited Production
HISTORIC NOTES The Radio Receptor Company, with factories in Brooklyn, NY, was one of a very few small electronics companies that moved quickly into the transistor business shortly after Western Electric began offering licenses to this new technology. In addition to a range of computer and hearing aid germanium alloy junction devices, Radio Receptor was the first to market a photo transistor, with the RR66 available in mid year 1954. The design was essentially a standard germanium alloy junction transistor, with a hermetically sealed glass top which allowed light to strike the transistor PN junctions. According to an August 1954 ad in the Proceedings of the IRE, the RR66 was suitable for such applications as industrial controls, punch cards and perforated tape readers, street light control, sound-on-film, burglar alarms, automatic door openers, and counters. Spectral response ranged from infrared though the complete tungsten lamp spectrum. A transistor very similar to the RR66 was introduced several years later by General Transistor Company as the GT66.
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