C1815 General Purpose NPN Transistor
= High-Gain NPN Transistor for General Amplification and Switching =
The C1815 is a widely used generalpurpose NPN silicon transistor designed for audio amplification and switching applications. Its high current gain and medium power handling make it suitable for lowpower audio amplifier stages, preamplifiers, and sensor circuits.
General Purpose NPN Transistor - Supports both amplification and switching functions
High Current Gain Range - hFE from 70 to 700 depending on grade selection
Collector-Emitter Voltage: 50V maximum
Collector Current: 150mA maximum
Collector Power Dissipation: 400mW in TO-92 package
Use the C1815 for audio preamplifier stages or to drive loads up to 150mA such as relays and LEDs
This transistor is available in TO92 (throughhole) and SOT-23 (SMD) packages
= Technical Specifications =
| Parameter | Value |
|---|
| Transistor Type | NPN |
| Package | TO92 or SOT23 |
| Collector-Emitter Voltage (VCEO) | 50V maximum |
| Collector-Base Voltage (VCBO) | 60V maximum |
| Collector Current (IC) | 150mA maximum |
| Power Dissipation (PC) | 400mW (TO-92) |
| Transition Frequency (fT) | 80MHz typical |
| Operating Temperature | -55°C to +150°C |
= Pinout (TO-92 Package) =
When viewing the flat face with leads pointing downward:
| Pin | Function |
|---|
| 1 | Emitter (E) |
| 2 | Collector (C) |
| 3 | Base (B) |
The pinout follows the ECB configuration for TO-92 package
For SOT-23 package, the pinout may differ: Base, Emitter, Collector
= hFE Classification Grades =
The C1815 is available in different gain ranks for optimal circuit performance :
| Rank | hFE Range |
|---|
| O | 70 - 140 |
| Y | 120 - 240 |
| GR | 200 - 400 |
| BL | 350 - 700 |
Grade is typically indicated by suffix after part number (e.g., 2SC1815-GR)
Choose grade based on the gain requirements of your specific application
= Key Features =
+High Current Gain - hFE up to 700 for strong signal amplification
+Good Frequency Response - 80MHz transition frequency suitable for audio applications
+Low Saturation Voltage - VCE(sat) typically 0.25V at 100mA for efficient switching
+Complementary PNP Pair - A1015 is the complementary PNP transistor
== Applications ==
- Audio preamplifiers and low-power amplifier stages
- Small-signal switching circuits
- Sensor signal conditioning and amplification
- Driver stage for relays and LEDs under 150mA
- Low-power RF and oscillator circuits
Reliable and Versatile A proven transistor for generalpurpose applications
Widely Available Common component in throughhole and SMD packaging
√ Compatible with 5V and 12V circuits
√ Good replacement for 2N3904 in many applications (check pinout compatibility)
√ Can be paired with A1015 for push-pull amplifier configurations
= Troubleshooting =
Transistor not switching:
- Verify baseemitter voltage is above 0.7V for turnon
- Check base current and resistor values
- Ensure load current does not exceed 150mA
Excessive heat:
- Verify collector current is within 150mA limit
- Ensure power dissipation does not exceed 400mW
- Check for proper biasing in amplifier circuits
