Introduction
The BC638 is a PNP silicon transistor designed for medium power amplification and switching applications in both analog and digital electronic circuits. It belongs to the well-known BC63x transistor family, which includes BC636, BC638, and BC640. With a collector current rating of up to 1A and a collector-emitter voltage (Vceo) of 60V, the BC638 provides excellent electrical performance for audio amplifiers, signal stages, and low-frequency driver circuits.
Housed in a TO-92 or TO-126 package, the BC638 is ideal for compact circuit designs that require efficient power handling and low heat dissipation. It is widely used in push-pull amplifier stages, complementary output configurations, and DC switching systems. The transistor features a stable DC current gain (hFE) and low collector-emitter saturation voltage, which ensures optimal linear amplification and efficient switching performance even under moderate load conditions.
BC638 PNP High Current Transistor
Thanks to its high reliability, thermal stability, and broad frequency response, the BC638 is a preferred choice in various audio, control, and signal processing circuits. It offers a balanced trade-off between voltage, current, and power dissipation, making it versatile for applications where medium voltage and current handling are required.
BC638 Pinout
Pin Configuration
| Pin# | Pin Name | Pin Description |
|---|---|---|
| 1 | Emitter (E) | Current flows out of the transistor; usually connected to the negative supply rail. |
| 2 | Base (B) | Controls transistor operation; a small base current regulates a larger collector current. |
| 3 | Collector (C) | The terminal through which load current passes when the transistor is active. |
Key Features
- PNP silicon transistor for medium-power amplification and switching
- High collector-emitter voltage (up to 60V)
- Maximum collector current up to 1A
- Excellent linearity for low-frequency audio amplification
- High DC current gain with thermal stability
- Low collector-emitter saturation voltage for efficient switching
- Suitable for complementary amplifier stages
- Compact and durable plastic package
Characteristics
- Transistor Type: PNP
- Collector-Emitter Voltage (Vceo): 60V
- Collector-Base Voltage (Vcbo): 60V
- Emitter-Base Voltage (Vebo): 5V
- Maximum Collector Current (Ic): 1A
- DC Current Gain (hFE): 40 to 250 (typical range)
- Power Dissipation (Ptot): 1.25W (in TO-126 package)
- Transition Frequency (fT): 50MHz
- Collector-Emitter Saturation Voltage (Vce(sat)): 0.3V typical
- Operating and Storage Temperature Range: -65°C to +150°C
- Package Type: TO-92 / TO-126
Comparison of BC636, BC638, BC640
- BC636 has the lowest collector-emitter voltage (45V) and is most suitable for low-voltage amplifier and switching applications.
- BC638 provides a higher voltage rating (60V) and improved power dissipation, making it ideal for medium-voltage circuits and robust amplifier designs.
- BC640 offers the highest voltage rating (80V) within this family, making it perfect for high-voltage and demanding power applications.
- Overall, the BC636 is best for general-purpose low-voltage use, BC638 strikes a balance between voltage and power handling, and BC640 delivers maximum voltage tolerance for advanced amplifier circuits.
More Circuit Layouts
Key Applications of BC638 Transistor
- Audio amplifier driver and output stages
- Low-frequency and preamplifier circuits
- Switching and control circuits
- Complementary push-pull amplifier configurations
- Power regulation and load driver applications
- Industrial and consumer electronics systems
NPN Complementary Transistor
- The BC638 transistor has the BC639 as its NPN complementary counterpart. Together, they form an excellent complementary pair for push-pull amplifier stages, output driver circuits, and audio output designs, providing symmetrical waveform amplification and efficient power transfer.
Equivalent of BC638 PNP Transistor
- BC636, BC640, 2N2907, BD136, BC327, 2SA733, 2SA1015
These equivalent transistors share similar characteristics and can be used as direct or near substitutes depending on the specific voltage, current, and power requirements of the circuit.
(Pin configuration of some transistors mentioned above may different from BC638).
Datasheet of BC638 PNP Transistor
Click the following Button to download the datasheet of BC638 Transistor :
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