Discrete transistors are transistors that are individually packaged.
The two main categories of packaging are
through-holeThrough-hole technology, also spelled "thru-hole", refers to the mounting scheme used for electronic components that involves the use of pins on the components that are inserted into holes drilled in printed circuit boards and soldered to pads on the opposite side.Through-hole technology almost...
(or
leaded), and
surface-mount, also known as
surface mount device (
SMDSurface-mount technology is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards . Electronic devices so made are called surface-mount devices or SMDs...
).
Transistor packages are made of glass, metal, ceramic or plastic. The package often dictates the power rating and frequency characteristics. Power transistors have large packages that can be clamped to
heat sinkA heat sink is an environment or object that absorbs and dissipates heat from another object using thermal contact...
s for enhanced cooling.
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Discrete transistors are transistors that are individually packaged.
The two main categories of packaging are
through-holeThrough-hole technology, also spelled "thru-hole", refers to the mounting scheme used for electronic components that involves the use of pins on the components that are inserted into holes drilled in printed circuit boards and soldered to pads on the opposite side.Through-hole technology almost...
(or
leaded), and
surface-mount, also known as
surface mount device (
SMDSurface-mount technology is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards . Electronic devices so made are called surface-mount devices or SMDs...
).
Transistor packages are made of glass, metal, ceramic or plastic. The package often dictates the power rating and frequency characteristics. Power transistors have large packages that can be clamped to
heat sinkA heat sink is an environment or object that absorbs and dissipates heat from another object using thermal contact...
s for enhanced cooling. Additionally, most power transistors have the collector or drain physically connected to the metal can/metal plate. At the other extreme, some surface-mount "microwave" transistors are as small as grains of sand.
Often a given transistor type is available in different packages. Transistor packages are mainly standardized, but the assignment of a transistor's functions to the terminals is not: different transistor types can assign different functions to the package's terminals. Even for the same transistor type the terminal assignment can vary (normally indicated by a suffix letter to the part number- i.e. BC212L and BC212K).
External links to datasheets
A wide range of transistors has been available since the 1960s and manufacturers continually introduce improved types. A few examples from the main families are noted below. Unless otherwise stated, all types are made from silicon semiconductor. Complementary pairs are shown as NPN/PNP or N/P channel. Links go to manufacturer datasheets, which are in PDF format. (On some datasheets the accuracy of the stated transistor category is a matter of debate.)
- 2N3904/2N3906, BC182/BC212 and BC546/BC556: Ubiquitous, BJT, general-purpose, low-power, complementary pairs. They have plastic cases and cost roughly ten cents U.S. in small quantities, making them popular with hobbyists.
- AF107
The AF107 is the European name for an early germanium-based bipolar junction transistor of PNP polarity intended for high frequency use . It shares most of its characteristics with the AF108. Both models use a non-standard round metallic housing of 9 millimetre diameter which is electrically...
: Germanium, 0.5 watt, 250 MHz PNP BJT.
- BFP183: Low power, 8 GHz microwave NPN BJT.
- LM394: "supermatch pair", with two NPN BJTs on a single substrate.
- 2N2219A/2N2905A: BJT, general purpose, medium power, complementary pair. With metal cases they are rated at about one watt.
- 2N3055/MJ2955: For years, the venerable NPN 2N3055 has been the "standard" power transistor. Its complement, the PNP MJ2955 arrived later. These 1 MHz, 15 A, 60 V, 115 W BJTs are used in audio power amplifiers, power supplies, and control.
- 2SC3281/2SA1302: Made by Toshiba
is a Japanese multinational conglomerate manufacturing company, headquartered in Tokyo, Japan. The company's main business is in infrastructure, consumer products, electronic devices and components.Toshiba-made Semiconductors are among the Worldwide Top 20 Semiconductor Sales Leaders...
, these BJTs have low-distortion characteristics and are used in high-power audio amplifiers. They have been widely counterfeitedhttp://sound.westhost.com/counterfeit.htm.
- BU508: NPN, 1500 V power BJT. Designed for television
Television is a widely used telecommunication medium for transmitting and receiving moving images, either monochromatic or color, usually accompanied by sound. "Television" may also refer specifically to a television set, television programming or television transmission...
horizontal deflection, its high voltage capability also makes it suitable for use in ignition systems.
- MJ11012/MJ11015: 30 A, 120 V, 200 W, high power Darlington complementary pair BJTs. Used in audio amplifiers, control, and power switching.
- 2N5457/2N5460: JFET
The junction gate field-effect transistor is the simplest type of field effect transistor. It can be used as an electronically-controlled switch or as a voltage-controlled resistance. Electric charge flows through a semiconducting channel between "source" and "drain" terminals...
(depletion mode), general purpose, low power, complementary pair.
- BSP296/BSP171: IGFET (enhancement mode), medium power, near complementary pair. Used for logic level conversion and driving power transistors in amplifiers.
- IRF3710/IRF5210: IGFET (enhancement mode), 40 A, 100 V, 200 W, near complementary pair. For high-power amplifiers and power switches, especially in automobiles.
External links