PN2222 was then introduced with the TO-92 package to replace 2N2222 and with the specification of 600-800mA depending on vendors.Īs said before, the current handling is highly depending on the package itself. TO-18 package loses its competitiveness and popularity.
TO-92 package has Pd of 1.5 W at 25 deg.C (Tc)ĢN2222 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 has Pd of 1.8 W at 25 deg.C (Tc). Power Dissipation, Pd = V x I = Vce(sat) x Ic The fundamental difference is the power handling or current (Ic) handling due to different package used. 🙂 “EEVBlog” linkĢN2222 is in the TO-18 metal package and 2N3904 is in the TO-92 plastic package. 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. Just a short and hopefully simple question. 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. Here are some popular comments from blogs.Ī 2N3904 can handle up to 200mA (milliamperes) of current flow from the emitter to the collector terminal. A different transistor's pins may be in the order b, c, e from left to right.Whenever you search for 2N3904, Google will suggest that 2N3904 vs 2N2222 as a popular search. This is especially true for transistors in the plastic TO-92 package.Īs an example, when the KSP2222 (or PN2222) transistor's flat side (the side with the part number printed on it) is facing you with the pins down, the pins are e, b, c (emitter, base, collector) from left to right. transistors with different part numbers) won't necessarily have the pins in the same order. 2N2222, BC107, BC108 and BC109 Transistor Pinout Diagramĭifferent transistors (i.e. The way that a 2N2222, BC107, BC108 and BC109 transistor symbol maps to the physical device is shown in the diagram below. Transistors have three pins called emitter (e), base(b) and collector(c). Metal Can and Plastic Packaged Transistors Transistors Pins The KSP2222 is an equivalent of the 2N2222 but is packaged in a plastic package known as a TO-92 package. The 2N2222 is packaged in a metal can package known as a TO-18 package. They have the part numbers 2N2222 and KSP2222 (also available as PN2222). In the photo below, two different transistors are shown. Transistor Part NumbersĮach transistor has a part number. 
The bigger the package is, the more power the transistor can handle. These are the names of the packages and not the transistor part numbers.
Transistors can be packaged in many different packages, some examples are shown below: Examples of Different Transistors in Different Packagesĭifferent packages have different names, e.g.
The symbols used in circuit diagrams for NPN and PNP transistors are shown below: Circuit Diagram Symbols of NPN and PNP Transistors Transistor Packages There are two types of BJTs, namely NPN and PNP. Here the BJT (Bi-polar Junction Transistor) is discussed. There are several kinds of transistors available, e.g.
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