TRANSISTOR MUSEUM Historic Transistor Photo Gallery
Transistor Size (3/16” Diameter X 5/16”) Date Code 427 (1954 Week 27) on Back Foldover Cardboard Envelope Packaging	CBS HYTRON PT-2A TYPE Germanium Point Contact Transistor USAGE Amplifier DATE INTRODUCED 1953 CASE STYLES Silver Metal Cylinder AVAILABILITY Rare (Limited Production)
HISTORIC NOTES CBS-Hytron introduced the PT-2A point contact transistor in 1953, with limited production. This transistor was designed for amplifier applications, while a similar unit, the PT-2S was designed for switching applications. Here is some text from the CBS datasheet: “ The PT-2A offers relatively high gain, low input impedance, and high output impedance. Gains of 18db are typical for the PT-2A when used in amplifier circuits of appropriate design.” The 1955 Lafayette “Money-Saver” catalogue lists the PT-2A as available for $2.90. This is the last year when point contact transistors were generally available, with junction transistor technology rapidly replacing point contact technology.
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