Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
TIP150 NTE Electronics, Inc.	T-NPN SI-HIV DARLINGTON	435
NTE2680 NTE Electronics, Inc.	TRANS NPN 800V 8A TO3PIS	774
BDV65 NTE Electronics, Inc.	TRANS NPN 60V 12A TO218	645
NTE2412 NTE Electronics, Inc.	TRANS NPN 300V 100MA SOT23	344
NTE159MCP NTE Electronics, Inc.	TRANS PNP 80V 800MA TO92	68
NTE2547 NTE Electronics, Inc.	TRANS NPN 100V 8A TO220	1432
2N5550 NTE Electronics, Inc.	T-NPN SI- HIV AMP	625
NTE2696 NTE Electronics, Inc.	T-NPN SI 120V IC=100MA TO-92	1066
MPSA42 NTE Electronics, Inc.	TRANS NPN 300V 500MA TO92-3	1420
NTE28 NTE Electronics, Inc.	TRANS PNP 45V 60A TO36	43
NTE121MP NTE Electronics, Inc.	TRANS PNP 45V 10A TO3	8
NTE16006 NTE Electronics, Inc.	TRANS NPN 20V 700MA 3SIP	419
NTE382 NTE Electronics, Inc.	TRANS NPN 100V 1A TO92L	4122
NTE225 NTE Electronics, Inc.	TRANS NPN 350V 1A TO39	37
NTE218 NTE Electronics, Inc.	TRANS PNP 80V 4A TO3	246
NTE24 NTE Electronics, Inc.	TRANS NPN 80V 1A TO237	55
2N6668 NTE Electronics, Inc.	TRANS PNP 80V 10A TO220AB	940
2N6107 NTE Electronics, Inc.	TRANS PNP 70V 7A TO220AB	166
NTE383 NTE Electronics, Inc.	TRANS PNP 100V 1A TO92L	2512
MPSA56 NTE Electronics, Inc.	SMALL SIGNAL BIPOLAR TRANSISTOR	98948

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