2N1560 semiconductor manufactured by Sylvania, listed as 2N1560 (circa 1979).

2N1559A semiconductor manufactured by Sylvania, listed as 2N1559A (circa 1979).

2N1559 semiconductor manufactured by Sylvania, listed as 2N1559 (circa 1979).

2N1558A semiconductor manufactured by Sylvania, listed as 2N1558A (circa 1979).

2N1558 semiconductor manufactured by Sylvania, listed as 2N1558 (circa 1979).

2N1557A semiconductor manufactured by Sylvania, listed as 2N1557A (circa 1979).

2N1557 semiconductor manufactured by Sylvania, listed as 2N1557 (circa 1979).

2N1556A semiconductor manufactured by Sylvania, listed as 2N1556A (circa 1979).

2N1556 semiconductor manufactured by Sylvania, listed as 2N1556 (circa 1979).

2N1555A semiconductor manufactured by Sylvania, listed as 2N1555A (circa 1979).

2N1555 semiconductor manufactured by Sylvania, listed as 2N1555 (circa 1979).

2N1554A semiconductor manufactured by Sylvania, listed as 2N1554A (circa 1979).

2N1554 semiconductor manufactured by Sylvania, listed as 2N1554 (circa 1979).

2N1553A semiconductor manufactured by Sylvania, listed as 2N1553A (circa 1979).

2N1553 semiconductor manufactured by Sylvania, listed as 2N1553 (circa 1979).

2N1552A semiconductor manufactured by Sylvania, listed as 2N1552A (circa 1979).

2N1552 semiconductor manufactured by Sylvania, listed as 2N1552 (circa 1979).

2N1551A semiconductor manufactured by Sylvania, listed as 2N1551A (circa 1979).

2N1551 semiconductor manufactured by Sylvania, listed as 2N1551 (circa 1979).

2N1550A semiconductor manufactured by Sylvania, listed as 2N1550A (circa 1979).