2SA1837 High Frequency PNP power Transistor

The 2SA1837 is a PNP high frequency power transistor. It has 3 pins namely a) Base b) Emitter and C) Collector. It has collector to emitter breakdown voltage of -230 V and collector current of -1 A. As mentioned in title it’s not an ordinary transistor in fact it is High Frequency PNP Power Transistor. The difference between normal transistor and high power transistor is that power transistor is capable of carrying more current than normal transistor without melting or burning. Using this package i.e. To-220F just with the help of single screw heat sink can be mounted on it. The visual appearance is illustrated in Figure .

2SA1837 Pins Assignment:

2SA1837 Pins Assignment is shown in Figure .  Turn non-flat side towards your face on the very left side of transistor at position 1) Base followed by 2) Collector and 3) Emitter. 

Pins Configuration of 2SA1837:

Pin Number

Pin Name

Pins Description



Used to turn ON and turn OFF the transistor (Biasing)



Current flows in through this and usually connected to load



For current to flow out, connected with ground.

Features of 2SA1837:

  • High transition frequency: 70 MHz
  • TO-220F package: Could easily be installed to heat sink with one screw
  • High current gain bandwidth product
  • Collector-base voltage: -230 V (Tc = 25 C)
  • Collector-emitter voltage: -230 V (Tc = 25 C)
  • Emitter-base voltage: -5 V (Tc = 25 C)

2SA1837 Equivalent:  2SA1006B, MJE15033

2SA1837 Complement: 2SC4793

Uses of 2SA1837 Transistor:

2SA1837 is a high frequency PNP power transistor with 3 pins. This 2SA1837 is a high current gain bandwidth product which can be used for different applications like power amplifiers and driver stage amplifiers. One should keep this in consideration while using this transistor, a continuous use of this transistor under heavy load may decrease its reliability even if it’s operating within maximum rating.

Working of 2SA1837 high frequency PNP power transistor: 

2SA1837 is a high frequency PNP power transistor. A transistor is a semiconductor device with its main function to amplify the weak signal; 2SA1837 is a type of power transistor with PNP configuration.

Generally transistor works almost similarly just difference is in their topology such as Bipolar PNP, NPN and similarly FET with N-channel and P-channel also how it is configured either common emitter, common base, common collector or else.

2SA1837 has three pins, in this PNP transistor current flow from emitter to collector pin whereas, base pin controls overall flow rate. It has property that it turns ON at very low signal that is an opposite of NPN transistor which turns ON at high signal.

2SA1837 high power transistor has different working regions i.e. Active region in which transistor works as an amplifier and is most versatile working region. The saturation or ON region is that region in which transistor operates as a closed or complete circuit. The final region is OFF or cutoff region in which it resembles as an open circuit.

2D Model of 2SA1837:

Below in Figure is 2D model which could help in detail construction considerations.

Video on Youtube: