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B7G base: Difference between revisions
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The 7-pin '''B7G tube base''' was developed in the late 1930s for miniaturized all-glass tubes. The earliest tubes using this base were commercially introduced in 1939, such as the [[6J6]]. | The 7-pin '''B7G tube base''' was developed in the late 1930s for miniaturized all-glass tubes. The earliest tubes using this base were commercially introduced in 1939, such as the [[6J6]]. | ||
The pins are arranged evenly in a circle of eight | The pins are arranged evenly in a circle of eight evenly spaced positions, with one pin omitted; this allows the tube to be inserted in only one orientation. The pins are stiff wires protruding through the bottom of the glass envelope and plug directly into the socket; the base is an integral part of the glass envelope. The pinched-off air evacuation nub is at the top of the tube. | ||
B9A is the most common base for tubes from the 1940s to the 1960s. | B9A is the most common base for tubes from the 1940s to the 1960s. | ||