- 2N1991
- Advanced Semiconductor, Inc.
- Silicon Transistor Selection Guide
- 2N1991
- Central Semiconductor Corp.
- 20 V, PNP, Si, SMALL SIGNAL TRANSISTOR, TO-18
- 2N1991LEADFREE
- Central Semiconductor Corp.
- 20 V, PNP, Si, SMALL SIGNAL TRANSISTOR, TO-18
- 2N1991
- Crimson Semiconductor
- Transistor Selection Guide
- 2N1991.MOD
- Semelab Plc.
- 300 mA, 20 V, PNP, Si, SMALL SIGNAL TRANSISTOR, TO-205AD
- 2N1991
- Semicoa Semiconductor
- General Purpose Medium Speed Amplifiers