2N4254 semiconductor manufactured by Sylvania, listed as 2N4254 (circa 1979).

2N4251 semiconductor manufactured by Sylvania, listed as 2N4251 (circa 1979).

2N4250A semiconductor manufactured by Sylvania, listed as 2N4250A (circa 1979).

2N4250 semiconductor manufactured by Sylvania, listed as 2N4250 (circa 1979).

2N4249 semiconductor manufactured by Sylvania, listed as 2N4249 (circa 1979).

2N4248 semiconductor manufactured by Sylvania, listed as 2N4248 (circa 1979).

2N4241 semiconductor manufactured by Sylvania, listed as 2N4241 (circa 1979).

2N4240 semiconductor manufactured by Sylvania, listed as 2N4240 (circa 1979).

2N4237 semiconductor manufactured by Sylvania, listed as 2N4237 (circa 1979).

2N4236 semiconductor manufactured by Sylvania, listed as 2N4236 (circa 1979).

2N4235 semiconductor manufactured by Sylvania, listed as 2N4235 (circa 1979).

2N4234 semiconductor manufactured by Sylvania, listed as 2N4234 (circa 1979).

2N4233 semiconductor manufactured by Sylvania, listed as 2N4233 (circa 1979).

2N4232 semiconductor manufactured by Sylvania, listed as 2N4232 (circa 1979).

2N4223 semiconductor manufactured by Sylvania, listed as 2N4223 (circa 1979).

2N4222A semiconductor manufactured by Sylvania, listed as 2N4222A (circa 1979).

2N4222 semiconductor manufactured by Sylvania, listed as 2N4222 (circa 1979).

2N4221A semiconductor manufactured by Sylvania, listed as 2N4221A (circa 1979).

2N4221 semiconductor manufactured by Sylvania, listed as 2N4221 (circa 1979).

2N4209 semiconductor manufactured by Sylvania, listed as 2N4209 (circa 1979).