2SC945 transistor
2SC945 transistor

2SC945 transistor specification

  • 2SC945 is High frequency amplifier NPN transistor type
  • Collector to emitter voltage is 40V
  • Collector to base voltage is 50V
  • Emitter to base voltage is 5V
  • Collector current is 1A
  • Base current is 20mA
  • Power dissipation is 250mW
  • DC current gain is 50 to 185hFE
  • Gain Bandwidth (FT) is 150 to 450MHz
  • Junction temperature is between –55 to 150
  • Noise figure (NF) is 15dB
  • Collector to emitter saturation voltage (VCE (SAT)) is3V
  • AF amplifier device
  • High voltage
  • Low-speed switching

2SC945 transistor Pinout

2SC945 transistor Pinout
2SC945 transistor Pinout
Pin Number Pin Name Description
1 Emitter Current flows through the emitter terminal
2 Collector Current flows through the collector
3 Base   The base is the trigger for the transistor 


2SC945 transistor package

The transistor package used at the 2SC945 device is the TO-92 package, it is a general-purpose transistor package mainly used at every common circuit, but the 2SC945 is not a common transistor.

The TO-92 is a package made with a combination of plastic and epoxy and also it’s a less compact package, so circuit design with this device will become less complex.

2SC945 transistor electrical specification description

The transistor 2SC945 is an AF amplifier high-frequency device, in this section we try to explain the electrical specs separately.

Voltage specs

The voltage specification of the 2SC945 transistor will be explained with terminal voltage specs, here we have collector to base voltage is 50V, collector to emitter voltage is 40V and emitter to base voltage is 5V, the voltage values state that 2SC945 transistor is a medium power device.

Current specs

The collector current value is 0.1A, the current value of the transistor shows the load capacity.

Dissipation specs

The power dissipation of this transistor will be 250Mw, it is the power capacity of the 2SC945 transistor, and we can also explain power dissipation as the heat capacity of the transistor.

Current gain specs

The current gain value is between 50 to 185hFE, it is an important value at amplifier and voltage regulation-related applications. 

Transition frequency/ Bandwidth frequency specs

The transition frequency value is explained with gain-bandwidth which is between 150 to 450MHz, this is an important spec for amplifier and switching-based applications.

Junction temperature

The junction temperature of -55 to 150℃, this is the most common temperature value for a medium power transistor device.

Noise figure

The noise figure value for the 2SC945 transistor is 15dB, the noise figure value is moderate for an amplifier device.  

2SC945 transistor DATASHEET

2SC945 transistor DATASHEET
2SC945 transistor DATASHEET

If you need the datasheet in pdf please click this link

2SC945 transistor equivalent

The transistors such as 2SC1815, 2SC2458, 2SC3198, 2SC3199, C945, and KSC3198 are the equivalent transistors for 2SC945.

Each of the transistors in this list had almost the same electrical specifications, we can easily replace 2SC945 with these transistors.

2SC945 vs 2SC1815 vs 2N3904

The table will explain the comparison between 2SC945 vs 2SC1815 vs 2N3904, electrical specs of each transistor will give us an idea about the transistor.

Characteristics 2SC945 2SC1815 2N3904
Collector to base voltage (VCB)50V60V60V
Collector to emitter voltage (VCE) 40V50V40V
Emitter to base voltage (VEB)5V5V6V
Collector current (IC)0.1A0.15A200mA
Power dissipation 250mW0.4W625mW
Junction temperature (TJ)150°C150°C150°C
Transition frequency (FT)150MHZ80MHZ250MHZ
Noise (N)15dB1dB6dB
Gain (hFE)50 to 185hFE70 to 700hFE30 to 300hFE
Package TO-92TO-92TO-92

The electrical specification table of three transistors states that each of the transistors had almost the same specifications.

The difference we can only see at transition frequency and DC current gain values, the transition frequency are higher at 2N3904 and 2SC1815 had higher DC gain value.

2SC945 transistor characteristics

graphical representation of collector current vs collector to emitter voltage
graphical representation of collector current vs collector to emitter voltage

The figure shows the graphical representation of collector current vs collector to emitter voltage, at each base current value, the collector current will rise at a level.

And the voltage becomes perpendicular with each range, the graph shows that at a certain level the collector current becomes constant.

characteristics curve of the 2SC945 transistor
characteristics curve of the 2SC945 transistor

The figure shows the characteristics curve of the 2SC945 transistor, the graph will be drawn between DC current gains vs collector current.

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