2pcs c1815 transistor

🔹 2PCS C1815 – NPN General-Purpose Silicon Transistor (TO-92)

A versatile and widely used NPN bipolar junction transistor (BJT) in the classic TO-92 package. The C1815 is a reliable, low-cost transistor ideal for small-signal amplification, switching, and general-purpose applications in audio, RF, and digital circuits. It is a popular complement to the PNP A1015.

✅ Specifications:

• Part Number: 2SC1815 (Commonly labeled as C1815)

• Type: NPN Bipolar Junction Transistor (BJT)

• Collector-Emitter Voltage (Vceo): 50V

• Collector-Base Voltage (Vcbo): 60V

• Emitter-Base Voltage (Vebo): 5V

• Continuous Collector Current (Ic): 150mA (Max)

• DC Current Gain (hFE): 70 to 700 (Graded: O=70-140, Y=120-240, GR=200-400, BL=350-700)

• Power Dissipation (Pc): 400mW (at 25°C ambient)

• Transition Frequency (fT): 80 MHz (Typical, good for RF/audio)

• Collector-Emitter Saturation Voltage (Vce(sat)): ~0.25V (Max at Ic=100mA, Ib=10mA)

• Noise Figure: Low, suitable for audio preamplifiers

• Package: TO-92 (Through-Hole, Plastic)

• Pinout (TO-92, flat side facing you, leads down):

  1. Emitter (E)

  2. Collector (C)

  3. Base (B)
     Always verify with a multimeter, as some manufacturers may use ECB pinout.

• Operating Temperature: -55°C to +150°C

• Quantity: 2 pieces

⚙️ Key Features:

• High Gain & Low Noise: Excellent for small-signal amplification in audio preamps, microphone amplifiers, and sensor interfaces.

• Good Frequency Response: The 80MHz fT makes it suitable for RF oscillator and amplifier stages up to VHF.

• Compact & Inexpensive: The ubiquitous TO-92 package is easy to prototype with and extremely cost-effective.

• Reliable Performance: A staple in consumer electronics and hobbyist projects for decades.

• Complementary Pair: Often used with its PNP counterpart, the A1015, for push-pull or complementary symmetry circuits.

📦 Typical Applications:

• Audio Preamplifiers: Low-noise voltage amplification for microphones, guitars, or line-level signals.

• Small Signal Switching: Driving LEDs, relays (with a base resistor), or other low-current loads from microcontroller GPIO pins.

• RF Oscillators & Amplifiers: Local oscillators, IF amplifiers, or buffer stages in radio circuits.

• Sensor Interface: Amplifying weak signals from photodiodes, thermistors, or other sensors.

• General Purpose Amplification: Any circuit requiring a simple, reliable NPN transistor for gain or switching.

🔧 Basic Configuration (Common-Emitter Amplifier):

1. Biasing: Requires proper DC biasing for linear amplification. A simple voltage divider (two resistors from Vcc to GND) sets the Base voltage.

2. Gain: Voltage gain ≈ RC/RE_RC_​/_RE_​, where RC_RC_​ is the collector resistor and RE_RE_​ is the emitter resistor (often bypassed with a capacitor for AC gain).

3. As a Switch (to drive an LED):

   • Connect LED + resistor from Vcc (e.g., 5V) to Collector.

   • Connect Emitter to GND.

   • Connect Base to a microcontroller pin via a current-limiting resistor (e.g., 1kΩ – 10kΩ).

   • Set the MCU pin HIGH to turn the transistor ON (saturate) and light the LED.

⚠️ Important Design Notes & Limitations:

• Low Current Device: Maximum 150mA collector current. Not for power switching (use TIP31C, TIP120, etc.).

• Heat Dissipation: Limited to 400mW. In linear mode, ensure VCE×IC<400mW_VCE_​×_IC_​<400_mW_.

• Gain Variability: The hFE has a very wide range. Circuits should be designed to work with the minimum specified gain (e.g., hFE=70) to ensure reliable operation across all parts.

• Unused Leads: For TO-92, the pinout is generally E-C-B (flat side facing you). Always verify with a multimeter in diode-test mode before soldering.

• ESD Sensitivity: Like all small-signal transistors, handle with care to avoid static damage.