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2SC945 / C945 TO-92 NPN Bipolar Transistor 50V (50pcs)
2SC945 / C945 TO-92 NPN Bipolar Transistor 50V (50pcs)
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2SC945 / C945 — TO-92 NPN Bipolar Transistor (50pcs)
The 2SC945 (commonly marked C945) is a classic Japanese-designed NPN small-signal transistor in TO-92 package, rated at 50V / 150mA. Widely used in audio preamplifier stages, signal switching, and general-purpose electronics. This listing provides a 50-piece pack — new and original parts.
Key Specifications
| Parameter | Value |
|---|---|
| Part Numbers | 2SC945 / C945 |
| Type | NPN Bipolar Junction Transistor (BJT) |
| Package | TO-92 |
| Collector-Emitter Voltage (Vceo) | 50V |
| Collector Current (Ic) | 150mA |
| Power Dissipation (Pd) | 250mW |
| hFE Groups | O: 70–140 / Y: 120–240 / GR: 200–400 / BL: 350–700 |
| Transition Frequency (ft) | 150MHz |
| Noise Figure | ≤4 dB |
| Operating Temperature | -55°C to +150°C |
| Quantity | 50 PCS |
Why Choose 2SC945?
- ✅ Low noise figure — ≤4 dB NF, ideal for audio preamp input stages
- ✅ High hFE range — up to 700 (BL grade) for high-gain amplifier stages
- ✅ 150MHz ft — suitable for RF and IF amplifier stages up to VHF
- ✅ TO-92 package — breadboard and PCB compatible
- ✅ 50-piece value pack — sufficient for production runs and repair stock
Compatible With / Works With
- Arduino UNO/Nano GPIO switching (5V logic to 50V load)
- NE555 timer output stage buffering
- LM386 audio amplifier input stage
- Japanese audio equipment repair (Sony, Panasonic, Pioneer)
- Complementary pair with 2SA733 (PNP) for push-pull audio stages
Typical Applications
- Audio Preamplifier — low-noise input stage for microphone and phono preamps
- Signal Switching — relay driver, LED driver from microcontroller GPIO
- RF/IF Amplifier — VHF signal amplification up to 150MHz
- Oscillator Circuits — Colpitts, Hartley oscillators for RF applications
- Japanese Equipment Repair — direct replacement in Sony/Panasonic audio boards
FAQ
Q: What do the hFE suffix letters mean (O, Y, GR, BL)?
A: These indicate the DC current gain group: O (70–140), Y (120–240), GR (200–400), BL (350–700). For audio circuits, GR or BL grade provides the most consistent gain. Check the marking on the flat face of the TO-92 package.
Q: Is 2SC945 equivalent to BC547 or 2N3904?
A: Functionally similar for general-purpose NPN switching. 2SC945 has lower noise figure (≤4 dB) and higher ft (150MHz vs 300MHz for BC547), making it preferred for audio and RF applications. Pinout differs — verify EBC orientation before substituting.
Q: What is the complementary PNP pair for 2SC945?
A: The complementary PNP is 2SA733 (C733). Together they form a matched NPN/PNP pair for push-pull audio output stages.
Package Contents
- 50× 2SC945 / C945 TO-92 NPN Bipolar Transistor
