How Motorola’s 2N2222 and 2N3904 transistors became the default NPNs

No later than last week I was fishing in my boxes for two pieces of 2N2222 for a pet project!

Just so long as we remember to check it'll fit the need. I recently inherited a design that used some parts from the 70s and they were not up to the task. Drop-out voltages too high, gate threshold voltages too high; whatever spec could be violated was. Just because it's been used for 50 years doesn't mean it's the right part for the job

The 2N3904 is an old friend who has never changed. I've been using him since the 80s and he's still my first choice whenever anything general-purposey comes along.

BC547? 337? I think they are Texas devices, much popular too.

This is an interesting article on how open licensing can help ensure viability long after the original designer has left the game.

Maybe in US. We had BC107-BC109 and BC177-BC179

No later than last week I was fishing in my boxes for two pieces of 2N2222 for a pet project!

This is an interesting article on how open licensing can help ensure viability long after the original designer has left the game.

The 2N3904 is an old friend who has never changed. I've been using him since the 80s and he's still my first choice whenever anything general-purposey comes along.

Maybe in US. We had BC107-BC109 and BC177-BC179

BC547? 337? I think they are Texas devices, much popular too.

Those were originally Philips devices, but like with the American JEDEC part names, after a device with an European part name, like BC337 was registered, any semiconductor device manufacturer could sell equivalent devices.

The European part numbers provided much more information than the American part numbers.

JEDEC 2Nxxxx just told you that this is some kind of transistor or thyristor, instead of being a diode like 1Nxxxx.

BC told you that this is a silicon small-power audio-frequency transistor.

There were separate codes for other materials and for many other kinds of transistors, diodes and thyristors (for example AD = germanium high-power audio-frequency transistor, BF/BL = Si low/high-power RF transistors, BS/BU = Si low/high-power switching transistors, BR/BT = Si low/high-power thyristors, BA/BY = Si low/high-power rectifiers, BB = Si varicaps, and many others).

Motorola and some other US companies, like Texas Instruments and Fairchild, entered the transistor market very early, when they defined types like 2N2222, which became industry standards.

However, because these devices were defined early, they had rather poor characteristics. When European companies like Philips, Siemens, Thomson, SGS-ATES entered the market later, they defined transistors and other devices with improved characteristics.

Because of this, in Europe the devices with European part numbers, like BC337, were generally preferred, because they provided better analog performance, e.g. lower noise and higher bandwidth.

However nowadays this has become mostly irrelevant, because a legacy transistor vendor makes only a small number of different kinds of transistors, distinguished mainly by die size, because bigger sizes are needed to handle bigger currents. Then the transistors are packaged and marked with any of the legacy part numbers, depending on what part number the customer orders.

So while old transistors may have quite different characteristics depending on the part name, many modern transistors behave the same, regardless how they are marked.

Exactly, I grew up playing with BC547 and BC337s (my father was an electronics engineer) and only later found 2N2222 and 2N3904. Those were almost entirely unheard of in India.

I think the BC548/558 were a bit more popular (though lower voltage) :)

(and I think you had it up to 546 with an ever higher voltage)

These parts that become "the part" often have this issue relatively early into the lifecycle. The 741 op-amp is another example. They are often bad and expensive, but they are a default so people put them in.

In fact, unless ubiquity in availability is a really core part of the design requirement, they almost certainly aren't the right part for the job.