S8550 PNP Bipolar Transistor – 25V 500mA TO-92
The S8550 PNP Transistor is a general-purpose bipolar junction transistor (BJT) designed for low-voltage switching, signal amplification, and electronic control applications.
Featuring a collector-emitter voltage rating of -25V and a continuous collector current rating of up to 500mA, the S8550 is suitable for small electronic loads, transistor switching circuits, and general-purpose amplifier designs.
Its compact TO-92 through-hole package makes it convenient for breadboard prototyping, PCB assembly, and DIY electronics projects.
The S8550 is commonly paired with complementary NPN transistors, such as the S8050, in suitable push-pull amplifier and switching circuits.
Key Features
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PNP Bipolar Transistor: Suitable for switching and signal amplification.
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500mA Collector Current: Supports small to moderate electronic loads.
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-25V Collector-Emitter Rating: Designed for low-voltage electronic circuits.
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DC Current Gain: hFE range of 85–300, depending on operating conditions and transistor grade.
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Compact TO-92 Package: Suitable for through-hole PCB assembly.
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General-Purpose Applications: Ideal for transistor switching, amplification, and electronic control circuits.
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Complementary Circuit Design: Can be used with suitable NPN transistors in push-pull configurations.
Technical Specifications
| Parameter |
Specification |
| Model |
S8550 |
| Transistor Type |
PNP Bipolar Junction Transistor |
| Package |
TO-92 |
| Mounting Type |
Through-Hole |
| Collector-Emitter Voltage (VCEO) |
-25V |
| Collector-Base Voltage (VCBO) |
-40V |
| Emitter-Base Voltage (VEBO) |
-5V |
| Maximum Collector Current (IC) |
500mA |
| DC Current Gain (hFE) |
85–300 |
| Number of Terminals |
3 |
| Terminal Functions |
Emitter, Base, Collector |
| Applications |
Switching and Signal Amplification |
Pin Configuration
The S8550 transistor has three terminals.
| Terminal |
Function |
| Emitter (E) |
Typically connected toward the positive supply in high-side switching circuits |
| Base (B) |
Controls transistor conduction |
| Collector (C) |
Connects to the controlled load or amplifier circuit |
Important: The physical pin arrangement may vary by manufacturer. Verify the exact pinout using the component marking and corresponding datasheet before connecting the transistor.
Applications
- Arduino and Microcontroller Switching Circuits
- High-Side Switching Applications
- Signal Amplification
- Audio Amplifier Circuits
- Class B Push-Pull Amplifiers
- LED Switching Circuits
- Transistor Driver Stages
- DIY Electronics Projects
- Educational Electronics
- PCB Prototyping
Important Notes
-
The S8550 is a PNP transistor, not an NPN transistor.
- A PNP transistor generally conducts when its base is driven sufficiently below its emitter voltage.
- Use a suitable base resistor to limit base current.
- Do not exceed the maximum collector current or voltage ratings.
- Use a flyback diode when switching inductive loads.
- The S8550 is not automatically interchangeable with other PNP transistors.
- Possible alternatives such as BC527, KSA708, and MPS750 require verification of electrical specifications and pin configuration before substitution.
- Actual current gain depends on operating conditions and device grade.
Package Includes
