If you want to compare transistors 2N3904 vs 2N2222, then you’ve come to the right place. The 2N3904 and 2N2222 are one of the two BJT NPN transistors most commonly used. I have personally used the 2N2222 a lot (see examples further below).
What’s different between 2N3904 vs 2N2222?
Maximum Ratings 2N3904 vs 2N2222:
|Collector – Base Voltage||60V||75V|
|Collector Current (continuous)||200mA||600mA|
Transistor Current Gain (hfe):
If you look at the spec sheet for both the 2N3904 vs 2N2222, you will see that both transistors can achieve a peak current gain of 100(min) to 300(max), the main difference is in the conditions that allow for such current gain. The 2N2222 experiences this peak at a collector current of 150mA and Collector – Emitter voltage of 10V, while the 2N3904 experiences this same peak at 10mA collector current and Collector – Emitter voltage of 1V. Both scenarios at 25 degrees Celsius (77 degrees Fahrenheit).
Either way, you wouldn’t design your system based on the peak current gain (that would be a bad idea). Now, what if you want to compare both transistors at similar conditions let’s take the peak current gain of the 2N3904 (current gain of 100 – 300) and compare it to the 2N2222 under the same conditions (25 degrees Celsius, 10mA Ic, and 1Vce). For that, let’s take a look at the following chart available on Onsemi’s website for 2N2222A (2N2222 on TO-92 packaging).
You can see that the current gain would be 200, which is in the same range as the min and max gain listed for the 2N3904 at the previously listed conditions. Net, there are differences in gain current, but I wouldn’t say they are major for most applications.
What’s the same between 2N3904 vs 2N2222?
Transistor type and pinout 2N3904 vs 2N2222
First, both transistor are BJT (Bipolar Junction Transistor) of the NPN type (Negative, Positive, Negative layer arrangement). The 2N2222 pinout and 2N3904 pinout are the same see below for their pinout based on the TO-92 plastic package:
Collector – Pin 1 (left most when looking at the flat size of the package).
Base – Pin 2 (middle pin).
Emitter – Pin 3 (right most when looking at the flat side of the package).
Many electrical properties are similar enough for simple applications. Even the current gain is similar enough (as previously discussed above), although clearly the current gain vs Vce curves are different. Net, there are some differences in max rating, and slight differences in some electrical characteristics, but for the most part, the two transistors are very similar, again, specially for simple applications. In terms of applications, both transistors can be used as an amplifier or a switch (the two traditional / typical applications for Bipolar Junction Transistors).
Variants of the 2N2222 transistor
Note that overtime, transistor suppliers started producing the 2N2222 transistor in the TO-92 package variant (plastic) instead of the 2N2222 TO-18 package variant (metal). The plastic variant is also known as 2N2222A, but is often referenced as 2N2222. In this page I have referenced the specifications of the 2N2222 in TO-92 package in order to compare both the 2N3904 and 2N2222 in similar package configurations. If you were to look at the 2N2222 in TO-18 you might notice that the current rating is higher than that of the 2N2222 in TO-92 package, which makes sense.
Examples using the 2N2222 transistor
If you’ve read through diyengineers.com, you might notice that I have used the 2N2222 / 2N2222A transistor in several example projects. So I wanted to invite you to take a look at some of them in case you are interested:
- HC-SR501 PIR Sensor – Learn how to use with Arduino
- How to use the 2N2222 Transistor (NPN) (with examples)
- RTC DS3231 – How to use with Arduino
- LDR sensor – How to use a Light Dependent Resistor
- LDR sensor with Arduino – How to use (with examples)
- Rotary Encoder with Arduino – Examples Included
Transistor Kit that you can use for future tests/projects:
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