TRANSISTOR MUSEUM Historic Transistor Photo Gallery
Transistor Size (5/16” Diameter X 3/8” H) Date Code 7L (1957)	RCA 2N247 TYPE Germanium PNP Alloy Junction Drift USAGE Hi Freq RF Amp/Oscillator Computer Switch DATE INTRODUCED 1957 CASE STYLES Black Metal (Early) Silver Metal (Later) AVAILABILITY Common (High Volume Production)
HISTORIC NOTES RCA pioneered the germanium “drift” transistor technology, primarily based on the work of Herbert Kroemer at RCA Labs in the mid 1950s. The 2N247 was the first commercially available drift transistor, and the excellent high frequency performance of this technology prompted RCA to introduce an entire series of germanium drift transistors over the next few years, including the 2N274, 2N370, 2N374, and 2N384. Until the development of the mesa transistor technology in the late 1950s, the Philco surface barrier technology and the RCA drift technology were the primary high speed/high frequency germanium transistor types. The 2N247 was available for approximately $3.00 from a variety of sources through the 1960s. Several of the early “high end” American-made multiband radio receivers, such as the Magnavox AW100, used RCA drift transistors in the RF/IF circuitry. Several models of the drift devices , such as the 2N247, were made with four leads, with the fourth lead being a shield/ground connected to the metal case of the transistor.
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