BC547 Bipolar Junction Transistors – BJT NPN 45V 100mA
The BC547 is a general‑purpose NPN silicon transistor designed for low‑current switching and amplification. With a collector‑emitter voltage rating of 45 V and a maximum collector current of 100 mA, it’s ideal for signal processing, driver stages, and interface applications in audio, instrumentation, and control circuits.
Features
Features- High Voltage Capability: VCEO = 45 V
- Moderate Current Handling: IC = 100 mA
- Low Saturation Voltages: VCE(sat) ≈ 90 mV @ 10 mA
- Wide hFE Gain Classification (A: 110–220, B: 200–450, C: 420–800)
- High Transition Frequency: fT ≈ 300 MHz
- Low Noise Figure: NF ≈ 2 dB
- Compact TO‑92 Package
Specifications
| Parameter | Symbol | Test Conditions | Min | Typ | Max | Units |
|---|---|---|---|---|---|---|
| Collector–Emitter Voltage | VCEO | – | – | – | 45 | V |
| Collector–Base Voltage | VCBO | – | – | – | 50 | V |
| Emitter–Base Voltage | VEBO | – | – | – | 5 | V |
| Collector Current (DC) | IC | – | – | – | 100 | mA |
| Power Dissipation | PC | – | – | – | 500 | mW |
| DC Current Gain | hFE | VCE = 5V, IC = 2mA | 110 | 110–800 | 800 | – |
| Saturation Voltage (C–E) | VCE(sat) | IC=10 mA, IB=0.5 mA | – | 90 | 200 | mV |
| Saturation Voltage (B–E) | VBE(sat) | IC=10 mA, IB=0.5 mA | – | 700 | 900 | mV |
| Transition Frequency | fT | VCE=5 V, IC=10 mA, f=100 MHz | – | 300 | – | MHz |
| Output Capacitance | Cob | VCB=10 V, IE=0, f=1 MHz | – | 3.5 | 6 | pF |
| Input Capacitance | Cib | VEB=0.5 V, IC=0, f=1 MHz | – | 9 | – | pF |
Applications
- Signal Amplification: Pre‑amplifiers, oscillators, and linear stages
- Switching: LED drivers, relay drivers, transistor‑transistor logic (TTL) interfaces
- Audio Circuits: Low‑noise stages in audio pre‑amps
- General‑Purpose: Analog/digital interface, sensor signal conditioning, hobbyist and educational projects