This article is part of a guided learning series exploring classic transistors and their modern variants available from DigiKey.
Canonical Article: What are Jellybean electronic components?
Closely Related Questions
This post answers the following closely related questions:
- Is the BC547 obsolete?
- Is the 2N2222 obsolete?
- Is the MPSA06 obsolete?
Summary
The 2N3904 and closely related transistors such as the 2N3906, 2N2222, 2N2907, BC107, BC177, BC547, and BC557 are not obsolete. DigiKey has hundreds of variants of these classic transistors.
Figure 1: Image of type 2N3906 TO-92 packaged transistors.
Answer
Customers occasionally ask if transistors such as the 2N3904, 2N2222, and BC547 are obsolete. This happens when they see the term obsolete in a web page.
This is not true.
In fact, these classic transistors are considered Jellybean components as defined in the canonical article.
These transistors:
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Are active and in production from multiple sources with highly competitive pricing
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Have staying power with some approaching 60 years old
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Have high stock levels at DigiKey, with some variants boasting over 1,000,000 available units (inclusive of variants, marketplace, and complementary devices).
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Have long been used in education textbooks and labs such as the famous Horowitz and Hill “Art of Electronics” textbook
How to Locate Jellybean Transistors at DigiKey
The DigiKey search engine allows the use of multiple keywords. The best way to locate transistor variants based on the original 2N3904 is to search DigiKey using keywords such as “3904 and BJT.” The same technique may be used for other transistors such as “2222 BJT” and “547 BJT” for variants of the 2N2222 and BC547 respectively.
This search technique recognizes that manufacturers often change the prefix and suffix for the core part numbers. These new part numbers accommodate variations such as:
- Lead-free
- Changes in packaging, such as an older TO-18 changed to a TO-92
- A wide variety of surface-mount variants sharing a similar die to the classic components
Continued reading:
For more information, please see these related pages for classic Jellybean transistors:
- 2N2222 and 2N2907 family
- BC107, BC547, and BC847 family
- 2N3904 and 2N3906 family
- MPSA06 and MPSA56 family
Parting Thoughts
Classic transistors such as the 2N3904 and 2N3906 have been with us for nearly 60 years. They and their variants are readily available from DigiKey.
Perhaps these are just the transistors you need for your project as a hedge against supply chain disruptions. In fact, I’ve heard it said, “You can use any transistor you want, but if it’s not a 2N3904 or a 2N3906 you must justify your design decision.” (Similar statements for the BC547 and BC847 for our European friends.)
Article by Aaron Dahlen, LCDR USCG (Ret.), Application Engineer at DigiKey. Author bio.