Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
NTE244 NTE Electronics, Inc.	TRANS PNP 80V 8A TO3	456
NTE287H NTE Electronics, Inc.	T-NPN SI HI VLTG	468
MJ10024 NTE Electronics, Inc.	T-NPN SI- HIV SW DARL	0
NTE293MP NTE Electronics, Inc.	TRANS NPN 50V 1A TO92L	6
NTE165 NTE Electronics, Inc.	TRANS NPN 700V 5A TO3	40
NTE124 NTE Electronics, Inc.	TRANS NPN 300V 1A TO66	984
NTE123AP-10 NTE Electronics, Inc.	TRANS NPN 40V 600MA TO92 10PK	5
NTE68MCP NTE Electronics, Inc.	TRANS PNP 250V 16A TO3	2
2N6052 NTE Electronics, Inc.	T-PNP SI-DARLINGTON AMP	27
NTE98 NTE Electronics, Inc.	TRANS NPN 500V 20A TO3	372
NTE186 NTE Electronics, Inc.	TRANS NPN 60V 3A TO202	230
NTE2314 NTE Electronics, Inc.	TRANS PNP 50V 15A TO3P	66
NTE264 NTE Electronics, Inc.	TRANS PNP 100V 10A TO220	404
BC558 NTE Electronics, Inc.	TRANS PNP 30V 100MA TO92-3	2176
NTE288H NTE Electronics, Inc.	T-PNP SI HI VLTG	104
PN3638A NTE Electronics, Inc.	TRANS PNP 25V 800MA TO92-3	932
NTE331 NTE Electronics, Inc.	TRANS NPN 100V 15A TO220	1682
NTE95 NTE Electronics, Inc.	TRANS NPN 250V 3A TO59	66
NTE89 NTE Electronics, Inc.	TRANS NPN 600V 6A TO3	40
TIP152 NTE Electronics, Inc.	T-NPN SI-HIV DARLINGTON	54

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