This Product Selection Guide contains information to help select products in the Single Bipolar Transistors category on DigiKey.com
Discrete Bipolar Junction Transistors (BJTs) are commonly used to construct analog signal amplification functions in audio, radio, and other applications. One of the first semiconductor devices to be mass produced, their characteristics are less favorable than those of other device types for applications involving high frequency switching and operation with high currents or voltages, but they remain a technology of choice for applications requiring analog signal reproduction with minimal added noise and distortion.
SelectionCharacteristics
Transistor Type: Enumerates product characteristics such as polarity, number of devices incorporated in a package, internal connections among devices, etc.
Current - Collector (Ic) (Max): The maximum current value the device can sustain at its collector without risking damage.
Voltage - Collector Emitter Breakdown (Max): The maximum voltage value the device can sustain at its collector without risking damage.
Vce Saturation (Max) @ Ib, Ic: Characterizes the voltage drop between a device’s collector and emitter terminals when a device is operated in saturation. Measured with the base and collector current values shown.
Current - Collector Cutoff (Max): Characterizes current flow through a device’s collector terminal when the device is in an “off” state.
DC Current Gain (hFE) (Min) @ Ic, Vce: Characterizes the ratio of collector current to base current for a bipolar transistor, under DC test conditions including the indicated values of collector current and collector-emitter voltage. Varies significantly among devices and with operating conditions.
Power - Max: Typically this represents the maximum power rating to which a device will meet its given specifications. Exceeding this power rating may damage the device and other system components.
Frequency - Transition: Characterizes a BJT’s frequency response, indicating the frequency at which a device’s current gain falls to a value of one.
Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.
Mounting Type: Indicates how the device is attached.
Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the supplier device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
Supplier Device Package: This is what the manufacturer calls the package of this device. They are manufacturer specific. It is typically best to use the actual dimensions from the datasheets rather than to go by this terminology when designing your circuit.
ProductExamples
| MFR PART # | 2N5401YBU |
|---|---|
| DIGI-KEY PART # | 2N5401YBUOS-ND |
| MANUFACTURER | onsemi |
| DESCRIPTION | Bipolar (BJT) Transistor PNP 150 V 600 mA 400MHz 625 mW Through Hole TO-92-3 |
| DATASHEET | Click Here |
| MFR PART # | MMBT3904,215 |
|---|---|
| DIGI-KEY PART # | 1727-4044-2-ND - Tape & Reel (TR) |
| MANUFACTURER | Nexperia USA Inc. |
| DESCRIPTION | Bipolar (BJT) Transistor NPN 40 V 200 mA 300MHz 250 mW Surface Mount TO-236AB |
| DATASHEET | Click Here |
| MFR PART # | TIP125 |
|---|---|
| DIGI-KEY PART # | 497-2618-5-ND |
| MANUFACTURER | STMicroelectronics |
| DESCRIPTION | Bipolar (BJT) Transistor PNP - Darlington 60 V 5 A 2 W Through Hole TO-220 |
| DATASHEET | Click Here |
| MFR PART # | MMBT3904LP-7B |
|---|---|
| DIGI-KEY PART # | MMBT3904LP-7BDITR-ND - Tape & Reel (TR) |
| MANUFACTURER | Diodes Incorporated |
| DESCRIPTION | Bipolar (BJT) Transistor NPN 40 V 200 mA 300MHz 250 mW Surface Mount X1-DFN1006-3 |
| DATASHEET | Click Here |
SchematicSymbol
Schematic symbol courtesy of Scheme-it. Please see their website for more information and symbols.
MediaLinks
Articles
Transistor Basics
2N3904 NPN Basic Transistor Guide
Product Training Modules
General Purpose Discrete Items - Toshiba
TechForum
Transistor Basics
2N3904 NPN Basic Transistor Guide
Finding a replacement for your Bipolar Transistor