2SC1815 (C1815) NPN Transistor – 50V 150mA TO-92

The 2SC1815, commonly marked C1815, is a general-purpose NPN bipolar junction transistor (BJT) designed for low-power switching, audio-frequency amplification and signal-processing applications.

Known for its good gain linearity and low-noise characteristics, the C1815 is widely used in audio circuits, preamplifiers, signal amplifiers, oscillator circuits and general electronic projects.

Its compact TO-92 through-hole package makes it suitable for breadboards, prototyping, educational projects and PCB designs.

Technical Specifications

• Part Number: 2SC1815 / C1815
• Transistor Type: NPN BJT
• Material: Silicon
• Collector-Emitter Voltage (VCEO): 50V Max.
• Collector-Base Voltage (VCBO): 60V Max.
• Emitter-Base Voltage (VEBO): 5V Max.
• Continuous Collector Current (IC): 150mA Max.
• Base Current (IB): 50mA Max.
• Collector Power Dissipation: 400mW Max. at 25°C
• DC Current Gain (hFE): 70–700, depending on gain classification
• Transition Frequency (fT): 80MHz Min.
• Collector-Emitter Saturation Voltage: 0.25V Max. at IC = 100mA, IB = 10mA
• Package: TO-92
• Mounting Type: Through-Hole

Low-Noise Amplification

The 2SC1815 is particularly well suited to audio-frequency and small-signal amplification.

Its low-noise characteristics make it useful in applications such as:

• Audio Preamplifiers
• Microphone Amplifiers
• Signal Amplifiers
• Audio Driver Stages
• Low-Level Analog Circuits

General-Purpose Switching

In addition to amplification, the C1815 can be used as a low-power electronic switch.

A small base current can control a larger collector current, allowing the transistor to interface electronic circuits with small loads.

Typical switching applications include:

• LED Control
• Small Relay Drivers
• Buzzer Control
• Signal Switching
• Logic Interface Circuits
• Microcontroller Projects

When driving inductive loads such as relays, a suitable flyback diode should be connected across the load.

Gain Classification

The 2SC1815 is available in different DC current gain (hFE) classifications.

Common classifications include:

• O: 70–140
• Y: 120–240
• GR: 200–400
• BL: 350–700

The actual gain range depends on the specific transistor supplied and its marking.

Complementary Transistor

The 2SA1015 (A1015) PNP transistor is commonly used as a complementary counterpart to the 2SC1815.

This combination is useful for complementary amplifier stages and other analog circuit designs.

Pin Configuration

For the traditional Toshiba-style 2SC1815 TO-92 package, the pin configuration is:

• Pin 1 – Emitter (E)
• Pin 2 – Collector (C)
• Pin 3 – Base (B)

Applications

Ideal for:

• Audio Amplifiers
• Preamplifier Circuits
• Signal Amplification
• Low-Noise Circuits
• Oscillator Circuits
• LED Switching
• Small Relay Drivers
• Arduino Projects
• Microcontroller Interfaces
• Educational Electronics
• Breadboard Prototyping
• General Electronic Circuits

Important Note

The 150mA collector-current rating is an absolute maximum rating and should not automatically be considered the recommended continuous operating current for every circuit.

Actual operating limits depend on collector-emitter voltage, base drive, ambient temperature, power dissipation and circuit design.

The transistor's pin configuration should always be verified before installation, especially when using 2SC1815-compatible parts from different manufacturers, as package and lead arrangements may vary.

For relay, motor, solenoid or other inductive-load applications, use an appropriate flyback protection diode.

Package Includes

1 × 2SC1815 (C1815) NPN Transistor – TO-92