Choosing the right transistor is the difference between a high-performance circuit and a pile of burnt silicon. At ElxHub, we categorize transistors into two main families: Bipolar Junction Transistors (BJT) for current-controlled tasks and Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFET) for high-efficiency voltage-controlled switching. This guide breaks down our library by application, power rating, and polarity to help you pick the perfect part.
The Master Transistor & MOSFET Comparison Table
Use this table to quickly find a transistor based on its maximum voltage (VCE or VDS) and current (IC or ID) handling capabilities.
| Part Number | Type | Polarity | Max Voltage | Max Current | Package | Best Use Case |
| BC547 | BJT | NPN | 45V | 100mA | TO-92 | Small Signal / Pre-amp |
| 2N3904 | BJT | NPN | 40V | 200mA | TO-92 | General Switching |
| 2N2222 | BJT | NPN | 40V | 800mA | TO-92 | High Speed Switch / Relays |
| BC337 | BJT | NPN | 45V | 800mA | TO-92 | Output Driver |
| TIP41C | BJT | NPN | 100V | 6A | TO-220 | Power Amplifier |
| TIP120 | Darlington | NPN | 60V | 5A | TO-220 | High-Gain Motor Driver |
| 2N3055 | BJT | NPN | 60V | 15A | TO-3 | Linear Power Supplies |
| BC557 | BJT | PNP | -45V | -100mA | TO-92 | Small Signal (Complement) |
| 2N3906 | BJT | PNP | -40V | -200mA | TO-92 | General Switching |
| BC327 | BJT | PNP | -45V | -800mA | TO-92 | Output Driver |
| TIP42C | BJT | PNP | -100V | -6A | TO-220 | Power (Complement) |
| TIP127 | Darlington | PNP | -60V | -5A | TO-220 | High-Gain High-Side Switch |
1. Small Signal & General Purpose BJTs
Best for switching small LEDs, amplifying sensor signals, or basic logic.
2. Power & Darlington BJTs
Best for driving heavy loads (motors, solenoids) where high current gain is required.
- High-Current NPN: TIP41C, 2N3055
- NPN Darlington: TIP120
- High-Current PNP: TIP42C
- PNP Darlington: TIP127
Selection Table: Quick Reference
| Requirement | Recommended Component |
| 5V Microcontroller Switching | 2N2222 (BJT) or IRLZ44N (Logic MOSFET) |
| High Power Audio Output | 2N3055 or TIP41C / TIP42C pair |
| Battery Powered Logic | 2N7000 or BS170 |
| Large DC Motor Control | IRFZ44N or TIP120 |
Related Tutorials & Resources
To understand how to implement these in your circuits, check out our other guides:
- Step-by-Step: How to Build a Logic Level Shifter using the 2N7000.
- Theory: Transistors – Basics, Types, and Working (Part of our Component Tutorials).
