2SC945 Bipolar NPN Transistor

11 September 2020 - 0 Comments

C945 Bipolar NPN Transistor

C945 Bipolar NPN Transistor Pinout

C945 Transistor Pinout Configuration

Pin Number	Pin Name	Description
1	Emitter	Current Drains out through emitter, normally connected to ground
2	Collector	Current flows in through collector, normally connected to load
3	Base	Controls the biasing of transistor, Used to turn ON or OFF the transistor

C945 Transistor Features

Japanese High frequency amplifier NPN Transistor
Current Gain (hFE) is 70 to 700 (high linearity)
Continuous Collector current (IC) is 150mA
Collector-Emitter voltage (VCEO) is 50 V
Collector-Base voltage (VCB0) is 60V
Emitter Base Voltage (VBE0) is 5V
Transition Frequency is 150MHz
Available only in To-92 Package

Complementary PNP for 2SC945

A733

Modern Replacement by ON Semiconductor

2N3904 (Pinouts are different)

Alternative for 2SC945

BC546, C1815, KSC945C

Warning: The C945 is a Japanese NPN transistor and hence the C945 pinout will be in Emitter, Collector, Base order. But for European transistors like BC546 the order will be as Emitter, Base and Collector. Normally during such replacements heat shrink tubes are used to cross over the Base and Collector pins without them getting into contact.

About C945 transistors

The C945 is an age old Japanese Bipolar audio frequency NPN transistor. It has a decent gain value (hfe) of maximum 700 and is highly linear. Hence it was widely used in amplifier applications for pre-amplifying purpose, in high frequency circuits. It is also used as oscillators with is complementary A733 PNP transistor.

When used as a switch it can easily by controlled by a MCU/MPU since it has a base voltage of only 5V. It can switch loads upto 50V but has a very low collector current rating of only 150mA so this transistor is not really a good choice to be used as a switch. A better alternative for switching applications will be 2N2222.

However this transistor is outdated and will not be easily available if you are in Asian or European countries. In that case you can try the 2N3904 transistor from ON semiconductors, but do remember to deal with the pinouts as mentioned in the warning section above.