2N3771 NPN Power Transistor

2N3771 Transistor
2N3771 Transistor
2N3771 Pinout
2N3771 Transistor
2N3771 Pinout

click on image to enlarge

The 2N3771 is a high current switching transistor that has a collector current of 30A. It is commonly used in Linear switching devices and power supply circuits.

Pin Configuration

Pin Number

Pin Name




Controls the biasing of transistor, Used to turn ON or OFF the transistor



Current flows in through collector, normally connected to load



Current Drains out through emitter, normally connected to ground



·         High Power NPN Transistor

·         DC Current Gain (hFE) 15 to 60

·         Continuous Collector current (IC) is 30A

·         Collector-Emitter voltage (VCE) is 40 V

·         Collector-Base voltage (VCB) is 50V

·         Emitter Base Voltage (VBE) is 5V

·         Available in To-3 Package


Note: Complete Technical Details can be found at the 2N3771 datasheet given at the end of this page.


Alternative for 2N3771

SK9134, NTE181, 2N5302, 2N5686


Brief Overview of 2N3771

The 2N3771 is a high power NPN transistor with a maximum collector current of 30A. The transistor also has a high collector to emitter voltage of 40V and low base threshold voltage of less than 5V, making it suitable for high current switching devices.

The transistor has a very low gain of 60 maximum, but yet because of the high current it is still used in few linear amplifiers. Most commonly it is used in power supply circuits and for switching inductive loads. The transistor comes in a To-3 package that is it will have only two leads Base and Emitter while the collector is the body of the transistor itself. The reason is that the collector will carry high current and hence the body will act as a heat sink due to its large surface area. If you are using them on PCB then securing it with nuts will form the collector connection. There are also mounting kits and wires which you can use if you are using them on testing boards.



  • Linear switching circuits

  • Small Amplifiers

  • Power supply circuits

  • Inductive load switching

  • high current switching (upto 20A) loads



2D dimensions will help you in placing this component at the time of making circuit on perf board or a PCB.

 2N3771 NPN Power Transistor 2-D Model


2N3771 NPN Power Transistor 2-D Model 

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