Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
NTE100 NTE Electronics, Inc.	TRANS PNP 24V 100MA TO5	17971
NTE159 NTE Electronics, Inc.	TRANS PNP 80V 800MA TO92	568
MJ10023 NTE Electronics, Inc.	T-NPN SI- HIV SW DARL	192
NTE126 NTE Electronics, Inc.	TRANS PNP 15V TO18	183
NTE250 NTE Electronics, Inc.	TRANS PNP 100V 16A TO3	238
NTE386 NTE Electronics, Inc.	TRANS NPN 500V 20A TO3	114
NTE101 NTE Electronics, Inc.	TRANS NPN 25V 300MA TO5	12
NTE193A NTE Electronics, Inc.	TRANS PNP 50V 500MA TO92HS	1023
2N6125 NTE Electronics, Inc.	TRANS PNP 60V 4A TO220	100
2N5038 NTE Electronics, Inc.	TRANS NPN 90V 20A TO3	2
NTE130 NTE Electronics, Inc.	TRANS NPN 60V 15A TO3	282
NTE184 NTE Electronics, Inc.	TRANS NPN 80V 4A TO126	978
NTE399 NTE Electronics, Inc.	T-NPN SI-VIDEO OUTPUT TO-92M	612
2N5303 NTE Electronics, Inc.	TRANS NPN 80V 20A TO3	40
NTE58 NTE Electronics, Inc.	TRANS NPN 200V 17A 3SIP	212
NTE280 NTE Electronics, Inc.	TRANS NPN 140V 12A TO3	80
NTE2697 NTE Electronics, Inc.	T-NPN SI 200V 7A TO-220	368
NTE2545 NTE Electronics, Inc.	TRANS NPN 60V 5A TO220	89
MPS4356 NTE Electronics, Inc.	T-PNP SI- AUDIO AMP	257
BDV64 NTE Electronics, Inc.	TRANS PNP 60V 12A TO218	640

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