2N3904 vs 2N2222, the history, and the true difference

2N3904 vs 2N2222

Whenever you search for 2N3904, Google will suggest that 2N3904 vs 2N2222 as a popular search. Here are some popular comments from blogs.

A 2N3904 can handle up to 200mA (milliamperes) of current flow from the emitter to the collector terminal. A 2N2222 can handle up to 5 times that amount since it can handle up to 1A (ampere) of current flow from the emitter to the collector to power on a load.

“Learning about Electronics” link

Just a short and hopefully simple question.
2N3904 = max 200mA
2N2222 = max 1A
Rest looks about the same
I am thinking why is the 2N3904 so popular, why not just use 2N2222 all the time or even maybe a max=5A all the time? I know that the price can differ but it’s about a few cents and to home use, it does not kill the budget. 🙂

“EEVBlog” link

The history and the true difference

2N2222 is in the TO-18 metal package and 2N3904 is in the TO-92 plastic package.

The fundamental difference is the power handling or current (Ic) handling due to different package used.

Power Dissipation, Pd = V x I = Vce(sat) x Ic

  • TO-18 package has Pd of 1.8 W at 25 deg.C (Tc)
  • TO-92 package has Pd of 1.5 W at 25 deg.C (Tc)

2N2222 was designed to handling higher current up to 1000mA, but the manufacturing cost of the TO-18 package is much higher than the TO-92 plastic package. TO-18 package loses its competitiveness and popularity.

PN2222 was then introduced with the TO-92 package to replace 2N2222 and with the specification of 600-800mA depending on vendors.

As said before, the current handling is highly depending on the package itself. 2N3904 has Ic rated limit of 200mA but theoretically, 2N3904 should be able to handle at least 600mA Ic.

Conclusion

As the demand for 2N2222 (TO-18) has dropped significantly or the suppliers don’t want to make it anymore. Some vendors simply supply a 2N2222 (TO-92 package) and marked as 2N2222 instead of PN2222.

The author was the global business manager of the Discrete division of National Semiconductor in Silicon Valley in the late ’80s.

You can now buy 2N2222 in the TO-92 package on the 1N4148.com site.

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