2N3691 semiconductor manufactured by Sylvania, listed as 2N3691 (circa 1979).

2N3690 semiconductor manufactured by Sylvania, listed as 2N3690 (circa 1979).

2N3689 semiconductor manufactured by Sylvania, listed as 2N3689 (circa 1979).

2N3688 semiconductor manufactured by Sylvania, listed as 2N3688 (circa 1979).

2N3687A semiconductor manufactured by Sylvania, listed as 2N3687A (circa 1979).

2N3687 semiconductor manufactured by Sylvania, listed as 2N3687 (circa 1979).

2N3686A semiconductor manufactured by Sylvania, listed as 2N3686A (circa 1979).

2N3686 semiconductor manufactured by Sylvania, listed as 2N3686 (circa 1979).

2N3685A semiconductor manufactured by Sylvania, listed as 2N3685A (circa 1979).

2N3685 semiconductor manufactured by Sylvania, listed as 2N3685 (circa 1979).

2N3684A semiconductor manufactured by Sylvania, listed as 2N3684A (circa 1979).

2N3684 semiconductor manufactured by Sylvania, listed as 2N3684 (circa 1979).

2N3682 semiconductor manufactured by Sylvania, listed as 2N3682 (circa 1979).

2N3678 semiconductor manufactured by Sylvania, listed as 2N3678 (circa 1979).

2N3677 semiconductor manufactured by Sylvania, listed as 2N3677 (circa 1979).

2N3673 semiconductor manufactured by Sylvania, listed as 2N3673 (circa 1979).

2N3672 semiconductor manufactured by Sylvania, listed as 2N3672 (circa 1979).

2N3671 semiconductor manufactured by Sylvania, listed as 2N3671 (circa 1979).

2N3667 semiconductor manufactured by Sylvania, listed as 2N3667 (circa 1979).

2N3666 semiconductor manufactured by Sylvania, listed as 2N3666 (circa 1979).