Bipolar NPN Transistor is an age-old Japanese Bipolar audio frequency NPN device. The transistor C945 has minimum & Maximum DC Current Gain (hFE): 70 – 700. Hence it was widely used in amplifier applications for pre-amplifying purpose in high-frequency circuits. It is also used as an oscillators with is complementary BC556, BC558 or any other PNP transistor.
As a switch it can be controlled by an MPU/MUC because it has a base voltage of only 5V. Transistor c945 can switch loads up to 50V but has a very low collector current rating of the only 150mA That is why C945 is not a good choice to be used in switch circuits. Transistor 2n222 is a better alternative for switching purposes.
Features Of C945 Transistor :
- Comes in package to-92.
- C945 NPN transistor is also known 2sc945.
- Max Collector current is 150 mA.
- Max Voltage Collector Emmiter is 50V.
- Collector power dissipation is 400 MW.
- it is Japanese NPN Transistor.
- Current Gain is 70 to 700.
- Continuous Collector current is 150mA.
- Collector-Emitter voltage is 50V.
- Collector-Base voltage is 60V.
- Emitter Base Voltage is 5V.
- Transition Frequency is 150MHz.
Specifications Of Amplifier High-Frequency OSC NPN Transistor:
- Case: TO92
- Type of transistor: NPN
- Polarisation: Bipolar
- Collector-Base Breakdown Voltage: 60V
- Collector-Emitter Breakdown Voltage: 50V
- Collector current: 150mA
- Power: 250mW
- Mounting: THT
- Frequency: 250MHz
Pin Description:
Pin desciription of C945 Transistor is described in the given below table for quick understanding.
| Pin Number | Pin Name | Description |
| 1 | Emitter | Current Drains out through emitter, usually connected to ground |
| 2 | Collector | Current flows in through collector, usually connected to load |
| 3 | Base | Used to turn ON or OFF the transistor ( load control) |
Alternative of transistor c945
BC547, 2SC1815, KSC945C, 2n222a
caution: The C945 is a Japanese NPN transistor so the pin out will be in Emitter, Collector, Base order. But for European transistors like BC546, BC547 and BC548 the order will be as Emitter, Base and Collector.
Modern Replacement by ON Semiconductor
2N3904 (Pin-Out may different so please check before replacement)
Complementary PNP for C945
A733, BC556, BC557
C945 Datasheet
Datasheet of transistor C945 is given in this pdf file.
Applications:
- Low current switches
- Pre-amplifiers
- H-bridge circuits for low power motors
- Audio frequency amplifier circuits
- Oscillator circuits