2N3904 NPN BJT in TO92 package

The 2N3904 is a commonly used NPN Bipolar Junction Transistor. There are a fair number of 2N3904 in the Joe Knows electronics semiconductor kit. Affiliate link added below.

2N3904 NPN BJT pin layout
2N3904 NPN BJT pin layout

As always, you need to be aware of the pin layout of any transistor you are using. While looking at the front of the 2N3904, and the pins pointing downwards, the left pin is the Emitter, the middle pin is the Base, and the right pin is the Collector. Always do a google search for the datasheet of any transistor you are using, to verify it’s pin layout.

Some 2N3904 basic electrical Properties:

These are Absolute maximum values according to 1 or more datasheets. Always consult datasheets yourself. Especially if you know the manufacturer of the component that you have.

  • Ic (Collector Current) 0f 200mA (Max).
  • hFE (DC current gain): Varies by amount of collector current. IC means collector current. 1mA = 0.001A.
      • IC = 0.1mA: min 60.
      • IC = 1mA: min 80.
      • IC = 10mA: min 100. and max. 300
      • IC = 50mA: min 60.
      • IC = 100mA: min 30.
  • TF (transition frequency): 300Mhz

Good topics to check out next:

 To support this site, check out the following links:

Home page

  • Information on this site is not guaranteed to be accurate. Always consult the manufacturer info/datasheet of parts you use. Research the proper safety precautions for everything you do.
  • Electronzap is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.