2SA991 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -60 V
• Collector-Base Voltage, max: -60 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -0.1 A
• Collector Dissipation: 0.5 W
• DC Current Gain (h_fe): 200 to 800
• Transition Frequency, min: 90 MHz
• Operating and Storage Junction Temperature Range: -55 to +125 °C
• Package: TO-92

The 2SA991 is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, collector, and base leads.
Here is an image showing the pin diagram of this transistor.The 2SA991 transistor can have a current gain of 200 to 800. The gain of the 2SA991E will be in the range from 400 to 800, for the 2SA991F it will be in the range from 300 to 600, for the 2SA991P it will be in the range from 200 to 400.Sometimes the "2S" prefix is not marked on the package - the 2SA991 might only be marked "A991".The complementary NPN transistor to the 2SA991 is the 2SC1844.You can replace the 2SA991 with the 2SA1285.