Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
NTE2665 NTE Electronics, Inc.	TRANS NPN 800V 28A TO3PBL	261
NTE16005 NTE Electronics, Inc.	TRANS NPN 75V 2A TO39	186
NTE2698 NTE Electronics, Inc.	T-NPN SI 200V 7A TO-3PN	372
NTE2331 NTE Electronics, Inc.	TRANS NPN 800V 6A TO3PML	424
NTE155 NTE Electronics, Inc.	TRANS NPN 32V 1A TO66	4412
NTE2324 NTE Electronics, Inc.	TRANS NPN 800V 8A TO3PML	1752
NTE159-10 NTE Electronics, Inc.	TRANS PNP 80V 800MA TO92 10PK	25
2N6338 NTE Electronics, Inc.	TRANS NPN 100V 25A TO204	22
NTE2677 NTE Electronics, Inc.	TRANS NPN 800V 10A TO3PIS	1580
TIP110 NTE Electronics, Inc.	TRANS NPN 60V TO220	821
NTE2348 NTE Electronics, Inc.	TRANS NPN 800V 12A TO3P	743
NTE152MP NTE Electronics, Inc.	TRANS NPN 90V 4A TO220	1
2N4398 NTE Electronics, Inc.	TRANS PNP 40V 30A TO3	171
NTE2517 NTE Electronics, Inc.	T-NPN SI HI CURRENT SW TO-126ML	126
NTE181MP NTE Electronics, Inc.	TRANS NPN 100V 30A TO3	48
2N6340 NTE Electronics, Inc.	TRANS NPN 140V 25A TO3	21
NTE180 NTE Electronics, Inc.	TRANS PNP 100V 30A TO3	256
NTE88MP NTE Electronics, Inc.	TRANS PNP 250V 10A TO3	1
NTE291 NTE Electronics, Inc.	TRANS NPN 120V 4A TO220	364
BC547A NTE Electronics, Inc.	TRANS NPN 45V 100MA TO92-3	30076

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