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2N2222A (TO-18 package) with the emitter, base and collector identified as E, B, and C respectively. 2N2222A and schema.jpg
2N2222A (TO-18 package) with the emitter, base and collector identified as E, B, and C respectively.

The 2N2222 is a common NPN bipolar junction transistor (BJT) used for general purpose low-power amplifying or switching applications. It is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds. It was originally made in the TO-18 metal can as shown in the picture.


The 2N2222 is considered a very common transistor, [1] [2] [3] and is used as an exemplar of an NPN transistor. It is frequently used as a small-signal transistor, [4] [5] and it remains a small general purpose transistor [6] of enduring popularity. [7] [8] [9]

The 2N2222 was part of a family of devices described by Motorola at a 1962 IRE convention. [10] Since then it has been made by many semiconductor companies, for example, Texas Instruments. [11]


The JEDEC registration of a device number ensures particular rated values will be met by all parts offered under that number. JEDEC registered parameters include outline dimensions, small-signal current gain, transition frequency, maximum values for voltage withstand, current rating, power dissipation and temperature rating, and others, measured under standard test conditions. Other part numbers will have different parameters. The exact specifications depend on the manufacturer, case type, and variation. Therefore, it is important to refer to the datasheet for the exact part number and manufacturer.

ST Microelectronics [12]
40 V800 mA500 mW/1.8 W300 MHz

All variations have a beta or current gain (hfe) of at least 100 in optimal conditions. It is used in a variety of analog amplification and switching applications.

Other NPN switching transistors

NPN silicon transistors with similar properties are also made in a variety of small through-hole and surface mount packages including TO-92, SOT-23, and SOT-223.

Replacements for the 2N2222 are commonly available now in the cheaper TO-92 packaging, where it is known as the PN2222 or P2N2222, which has similar specifications except for the lower maximum collector current. [13] The P2N2222 has a different order of pins than the metal case 2N2222, with its emitter and collector connections switched; other plastic-case transistors also have different pinouts.

Single transistors are also available in several different surface mount packages, and a number of manufacturers market surface mount packages that incorporate several 2N2222-type transistors in one package as an array of transistors. The general specifications of the various variants are similar, with the biggest difference being the maximum allowable current and power dissipation.

The BC548 is a low voltage, low current, general-purpose switching transistor in a TO-92 package.

The 2N2907 is an equally popular PNP transistor complementary to the 2N2222. [14]

The 2N3904 is an NPN transistor that can only switch one-third the current of the 2N2222 but has otherwise similar characteristics. The 2N3904 exhibits its forward gain (beta) peak at a lower current than the 2N2222, and is useful in amplifier applications with reduced Ic, e.g., (gain peak at 10 mA for the 2N3904 but 150 mA for the 2N2222).

The 2N2219 is very similar with higher power dissipation rating.

Part numbers

The 2N2222 (NPN) and 2N2907 (PNP) are complementary transistor pairs.

Transistor part numbers
BJT Thru-hole Surface-mount
TO 18 SOT23 SOT223
PNP 2N2907 MMBT2907PZT2907A

See also

Related Research Articles

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Emitter-coupled logic high-speed integrated circuit bipolar transistor logic family

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The Schottky diode, also known as Schottky barrier diode or hot-carrier diode, is a semiconductor diode formed by the junction of a semiconductor with a metal. It has a low forward voltage drop and a very fast switching action. The cat's-whisker detectors used in the early days of wireless and metal rectifiers used in early power applications can be considered primitive Schottky diodes.

TRIAC generic trademark for a three-terminal thyristor that conducts current in either direction when triggered

TRIAC is a generic trademark for a three terminal electronic component that conducts current in either direction when triggered. Its formal name is bidirectional triode thyristor or bilateral triode thyristor. A thyristor is analogous to a relay in that a small voltage induced current can control a much larger voltage and current. The illustration on the right shows the circuit symbol for a TRIAC where "A1" is Anode 1, "A2" is Anode 2, and "G" is Gate. Anode 1 and Anode 2 are normally termed Main Terminal 1 (MT1) and Main Terminal 2 (MT2) respectively.

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Push–pull output

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The 2N3055 is a silicon NPN power transistor intended for general purpose applications. It was introduced in the early 1960s by RCA using a hometaxial power transistor process, transitioned to an epitaxial base in the mid-1970s. Its numbering follows the JEDEC standard. It is a transistor type of enduring popularity.

Texas Instruments Power, known more popularly by its acronym TIP, is a series of bipolar junction transistors manufactured by Texas Instruments. The series was introduced in the 1960s, and still sees some use today due to their simplicity, their durability, and their ease of use. A Texas Instruments catalog in 1966 lists the TIP04 and TIP14 part numbers.


In electronics, TO-3 is a designation for a standardized metal semiconductor package used for power semiconductors, including transistors, silicon controlled rectifiers, and, integrated circuits. TO stands for "Transistor Outline" and relates to a series of technical drawings produced by JEDEC.

2N3904 NPN transistor

The 2N3904 is a common NPN bipolar junction transistor used for general-purpose low-power amplifying or switching applications. It is designed for low current and power, medium voltage, and can operate at moderately high speeds.

The 2N2907 is a commonly available PNP bipolar junction transistor used for general purpose low-power amplifying or switching applications. It is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds. This transistor was made by several manufacturers; Texas Instruments released a data sheet for their version of this part dated March 1973. An "A" suffix indicates a slightly higher breakdown voltage. These transistors have an enduring popularity with electronics hobbyists.

2N3906 PNP transistor

The 2N3906 is a commonly used PNP bipolar junction transistor intended for general purpose low-power amplifying or switching applications. It is designed for low electric current and power and medium voltage, and can operate at moderately high speeds.

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The 1N4148 is a standard silicon switching signal diode. It is one of the most popular and long-lived switching diodes because of its dependable specifications and low cost. Its name follows the JEDEC nomenclature. The 1N4148 is useful in switching applications up to about 100 MHz with a reverse-recovery time of no more than 4 ns.

BC548 general-purpose NPN bipolar junction transistor

The BC548 is a general-purpose NPN bipolar junction transistor commonly used in European and American electronic equipment. It is notably often the first type of bipolar transistor hobbyists encounter and is often featured in designs in hobby electronics magazines where a general-purpose transistor is required. The BC548 is low in cost and widely available.


TO-126 is a type of semiconductor package for devices with three pins, such as transistors. The package is rectangular with a hole in the middle to allow for easy mounting to a board or a heat sink.

The BC107, BC108 and BC109 are general-purpose low power silicon NPN bipolar junction transistors found very often in equipment and electronics books/articles from Europe, Australia and many other countries. They were created by Philips and Mullard in 1963 and introduced in April 1966. Initially in metal (TO-18) packages, the range expanded over time to include other package types, higher voltage ratings, and a better selection of gain groupings, as well as complementary PNP types. Some manufacturers have specified their parts with a higher power dissipation rating (Ptot) than others.


  1. Dan O'Sullivan, Tom Igoe; "Physical Computing"; Cengage Learning; pp.19; 2004; ISBN   1-59200-346-X
  2. Brad Graham, Kathy McGowan; "Mind Performance Projects for the Evil Genius"; McGraw Hill Professional; pp.18; 2010; ISBN   978-0-07-162392-6
  3. Brad Graham, Kathy McGowan; "51 High-Tech Practical Jokes for the Evil Genius"; McGraw Hill Professional; pp.12; 2007; ISBN   978-0-07-149494-6
  4. Gordon McComb; "The Robot Builder's Bonanza"; McGraw-Hill Professional; 2001; pp.261; ISBN   978-0-07-136296-2
  5. William Rynone; "Linear Active Circuits Design and Analysis"; Artech House; pp.19; 1986; ISBN   0-89006-199-8
  6. Dennis Barnaal, "Analog and Digital Electronics for Scientific Application"; Breton Publishers; pp.301; 1982; ISBN   0-534-01044-X
  7. Rudolf F. Graf and William Sheets (2001). Build your own low-power transmitters: projects for the electronics experimenter. Newnes. p. 14. ISBN   978-0-7506-7244-3. The 2N2222, 2N2905, and 2N3055 devices, for example, which date back to the 1960s but have been improved, are still useful in new designs and are still popular for experimenters.
  8. Ed Da Silva (2001). High frequency and microwave engineering. Newnes. p. 263. ISBN   978-0-7506-5046-5. Typical examples are the well known NPN and PNP industrial and military types, 2N2222 and 2N2907, which have been used for over four decades and are still being used in many designs.
  9. Jack Ward. "THE DEVELOPMENT OF THE 2N2222: The Most Successful and Widely Used Transistor Ever Developed!". The Transistor Museum. Archived from the original on 14 April 2011. Retrieved 26 March 2011. Since its initial product launch by Motorola at the 1962 IRE Convention, the 2N2222 has become the most widely used and universally recognized transistor of all time. Billions of units have been manufactured over the past 45 years and there is continuing high volume annual production.
  10. http://www.semiconductormuseum.com/Transistors/Motorola/Haenichen/Haenichen_Page11.htm Haenichen oral history retrieved from the Semiconductor Museum 2011 May 13
  11. The Transistor and Diode Data Book for Design Engineers, Texas Instruments Incorporated, no date, TI publication number CC413 71242-73-CSS, page 4-93
  12. http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00003223.pdf Datasheet accessed 2013-10-26
  13. http://www.fairchildsemi.com/ds/PN/PN2222.pdf Archived 27 September 2007 at the Wayback Machine Retrieved 3 June 2012
  14. Dave Hrynkiw and Mark W. Tilden (2002). Junkbots, bugbots, and bots on wheels: building simple robots with BEAM technology. McGraw-Hill Professional. p. 44. ISBN   978-0-07-222601-0. Learn to keep an eye open for the following transistors, as they're among the most useful, inexpensive, and popular types: PN2222/PN2907 These are general-purpose NPN/PNP transistors that can drive some good amounts of power. They're listed together because they're complementary transistors.

Further reading

Historical Databooks