Transistors - Bipolar (BJT)

Transistors - Bipolar (BJT) - Single

Part Number	Description / PDF	Quantity
TIP30A NTE Electronics, Inc.	TRANS PNP 60V 1A TO220AB	260
NTE53 NTE Electronics, Inc.	TRANS NPN 400V 15A TO3	2135
NTE68 NTE Electronics, Inc.	TRANS PNP 250V 16A TO3	189
BC337 NTE Electronics, Inc.	SMALL SIGNAL BIPOLAR TRANSISTOR	24412
2N4123 NTE Electronics, Inc.	T-NPN SI- GEN PUR AMP	7046
NTE374 NTE Electronics, Inc.	TRANS PNP 160V 1.5A TO126	179
NTE36 NTE Electronics, Inc.	TRANS NPN 140V 12A TO3P	468
NTE61MCP NTE Electronics, Inc.	TRANS PNP 140V 20A TO3	8
NTE74 NTE Electronics, Inc.	TRANS NPN 100V 7A TO59	53
NTE2304 NTE Electronics, Inc.	TRANS NPN 50V 15A TO3P	596
NTE104 NTE Electronics, Inc.	TRANS PNP 35V 10A TO3	27
NTE128 NTE Electronics, Inc.	TRANS NPN 80V 1A TO39	1106
NTE2426 NTE Electronics, Inc.	TRANS NPN 80V 500MA SOT89	2298
2N6039 NTE Electronics, Inc.	NPN DARLINGTON POWER TRANSISTOR	2137
NTE242 NTE Electronics, Inc.	TRANS PNP 80V 4A TO220	1197
MPSA06 NTE Electronics, Inc.	TRANS NPN 80V 500MA TO92-3	1650
NTE2406 NTE Electronics, Inc.	TRANS NPN 40V 600MA SOT23	724
NTE289MP NTE Electronics, Inc.	TRANS NPN 30V 800MA TO92	17
TIP35A NTE Electronics, Inc.	T-NPN SI- PWR AMP	515
2N2405 NTE Electronics, Inc.	TRANS NPN 90V 1A TO39	291

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