Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
NTE39 NTE Electronics, Inc.	TRANS PNP 300V 500MA TO126	60
2N5771 NTE Electronics, Inc.	SMALL SIGNAL BIPOLAR TRANSISTOR	0
MJ15015 NTE Electronics, Inc.	T-NPN SI HIGH POWER AUDIO TO-3	65
NTE47 NTE Electronics, Inc.	TRANS NPN 45V 200MA TO92	360
MJ10016 NTE Electronics, Inc.	T-NPN SI- PO HIV DARL	220
NTE162 NTE Electronics, Inc.	T-NPN SI-VERT DEFL TO-3	170
NTE2301 NTE Electronics, Inc.	TRANS NPN 750V 5A TO218	56
NTE2352 NTE Electronics, Inc.	TRANS PNP 80V 4A 3SIP	45
MJE13005 NTE Electronics, Inc.	TRANS NPN 400V 4A TO220AB	7
NTE2318 NTE Electronics, Inc.	TRANS NPN 700V 8A TO218	279
NTE324 NTE Electronics, Inc.	TRANS NPN 120V 1A TO39	188
2N6488 NTE Electronics, Inc.	TRANS NPN 80V 15A TO220AB	68383
NTE248 NTE Electronics, Inc.	TRANS PNP 100V 12A TO3	518
TIP145 NTE Electronics, Inc.	TRANS PNP 60V 10A TO218	513
2N5400 NTE Electronics, Inc.	TRANS PNP 120V 600MA TO92-3	4743
NTE2366 NTE Electronics, Inc.	TRANS PNP 300V 100MA TO92L	87
TIP101 NTE Electronics, Inc.	TRANS NPN 80V 8A TO220	1106
NTE153MCP NTE Electronics, Inc.	TRANS PNP 90V 4A TO220	11
NTE32 NTE Electronics, Inc.	T-PNP SI VERT/SND OUTPUT TO-92M	187
NTE123AP NTE Electronics, Inc.	TRANS NPN 40V 600MA TO92	5435

Transistors - Bipolar (BJT) - Single

1. Overview

Bipolar Junction Transistors (BJTs) are three-terminal semiconductor devices that use both electron and hole charge carriers. They form the foundation of analog electronics through their ability to amplify signals and control current flow. BJTs remain critical in modern electronics for applications ranging from audio amplifiers to power management circuits, offering superior linearity and robustness in switching operations.

2. Main Types & Functional Classification

Type	Functional Characteristics	Application Examples
NPN Transistor	Majority carriers: electrons. Requires positive base current for conduction.	Low-noise amplifiers, digital logic circuits
PNP Transistor	Majority carriers: holes. Conducts with negative base current.	Power supply circuits, motor controllers
High-Frequency BJT	Optimized for RF/microwave signal amplification (f_T > 100 MHz)	Wireless communication systems, radar
Power BJT	High current/voltage ratings (I_C > 1A, V_CE > 50V)	Switch-mode power supplies, motor drives

3. Structure & Composition

BJTs consist of three doped semiconductor regions forming two p-n junctions:

Emitter: Heavily doped region emitting charge carriers
Base: Thin, lightly doped middle region controlling carrier flow
Collector: Moderately doped region collecting carriers

Manufactured using silicon (common) or germanium (historic) with planar processing technology. The structure forms either NPN (n-type emitter/base/collector) or PNP configuration, with metal contacts for external connections.

4. Key Technical Specifications

Parameter	Description	Importance
Current Gain (h_FE)	Ratio of collector to base current (10-1000)	Determines amplification capability
Transition Frequency (f_T)	Frequency at which current gain drops to 1	Limits high-frequency performance
Max Collector Current (I_Cmax)	Maximum allowable continuous collector current	Defines power handling capability
Breakdown Voltage (V_CEO)	Max voltage between collector and emitter	Prevents device failure under stress
Saturation Voltage (V_CEsat)	Voltage drop in fully conducting state	Affects power efficiency in switching

5. Application Areas

Consumer Electronics: Audio amplifiers, LED drivers
Automotive: Engine control units, electric vehicle inverters
Industrial: PLCs, motor controllers
Telecommunications: RF power amplifiers, fiber optic transceivers
Aerospace: Avionics systems, satellite transponders

6. Leading Manufacturers & Products

Manufacturer	Product Series	Key Specifications	Typical Use
ON Semiconductor	2N3904	hFE: 100-300, fT: 300 MHz	General-purpose switching
Infineon	BC547	VCEO: 50V, ICmax: 100mA	Analog signal amplification
STMicroelectronics	2SD2656	ICmax: 15A, VCEO: 80V	Power inverter applications
Diodes Inc.	BFR93A	fT: 10 GHz, Noise Figure: 2dB	High-frequency front-end amplifiers

7. Selection Guidelines

Determine operating frequency: Select fT > 3 target frequency
Power requirements: Ensure Icmax and VCEO exceed circuit requirements by 20%
Thermal considerations: Calculate power dissipation (P=V_CE I_C)
Package type: TO-92 for low power, TO-220 for high-power applications
Environmental factors: Consider temperature ratings for industrial/military use

8. Industry Trends

Future developments include:

High-frequency BJTs operating beyond 100 GHz for 6G communication
Integrated BJT-MOSFET hybrid devices (BiCMOS) for mixed-signal applications
Wide-bandgap materials (SiC/GaN) for higher power density
Miniaturization through chip-scale packaging
Improved thermal management solutions for automotive applications