2N1667 semiconductor manufactured by Sylvania, listed as 2N1667 (circa 1979).

2N1666 semiconductor manufactured by Sylvania, listed as 2N1666 (circa 1979).

2N1665 semiconductor manufactured by Sylvania, listed as 2N1665 (circa 1979).

2N1664 semiconductor manufactured by Sylvania, listed as 2N1664 (circa 1979).

2N1663 semiconductor manufactured by Sylvania, listed as 2N1663 (circa 1979).

2N1653 semiconductor manufactured by Sylvania, listed as 2N1653 (circa 1979).

2N1652 semiconductor manufactured by Sylvania, listed as 2N1652 (circa 1979).

2N1651 semiconductor manufactured by Sylvania, listed as 2N1651 (circa 1979).

2N1646 semiconductor manufactured by Sylvania, listed as 2N1646 (circa 1979).

2N1644A semiconductor manufactured by Sylvania, listed as 2N1644A (circa 1979).

2N1644 semiconductor manufactured by Sylvania, listed as 2N1644 (circa 1979).

2N1643 semiconductor manufactured by Sylvania, listed as 2N1643 (circa 1979).

2N1642 semiconductor manufactured by Sylvania, listed as 2N1642 (circa 1979).

2N1641 semiconductor manufactured by Sylvania, listed as 2N1641 (circa 1979).

2N1640 semiconductor manufactured by Sylvania, listed as 2N1640 (circa 1979).

2N1639 semiconductor manufactured by Sylvania, listed as 2N1639 (circa 1979).

2N1638 semiconductor manufactured by Sylvania, listed as 2N1638 (circa 1979).

2N1637 semiconductor manufactured by Sylvania, listed as 2N1637 (circa 1979).

2N1636 semiconductor manufactured by Sylvania, listed as 2N1636 (circa 1979).

2N1635 semiconductor manufactured by Sylvania, listed as 2N1635 (circa 1979).