BC327 PNP Transistor Pinout, Datasheet, Circuit, Equivalent & Uses

Published:January 24, 2024

Dr. James Anderson is a distinguished figure in electrical engineering, specialising in electronic components. Dr. Anderson has dedicated his career to pushing the boundaries of electronic component technology. With over 20 years of experience in academia and industry, he has earned a reputation as a leading expert.

At the core of electronics, there beats a rhythm driven by minuscule titans known as transistors. These exceptional semiconductors serve as diminutive gatekeepers, enhancing signals, regulating current flow, and laying the foundation for innumerable devices.

Picture a switch governed by electricity, not just the touch of a finger. This encapsulates the nature of a transistor, and within this category, PNP transistors, such as the BC327, command a special spotlight.

In contrast to their NPN counterparts, PNP transistors engage in a distinct electrical choreography. They conduct when a positive voltage energizes their base, enabling current to traverse from collector to emitter. This seemingly subtle distinction unlocks a distinctive potential in circuits, rendering PNP transistors indispensable for signal inversion, handling higher voltages and currents, and constructing push-pull amplifiers. In this article, we'll delve into the BC327 PNP transistor, exploring its pinout, datasheet, circuit, equivalents, uses and more details. Everything you need to know about this transistor.



What is BC327?

The BC327 stands as a versatile PNP BJT transistor, with its base requiring a connection to the ground to activate it. This transistor finds common application in both switching and amplification scenarios.

In the transistor's off state, a positive voltage is observed on the base when measuring the voltage between the base and the emitter. According to the transistor's characteristics, a minimal amount of current must exit the base to trigger the transistor, resulting in a positive voltage on the base and initiating leakage current from the base to the ground. The characteristic curve below illustrates that a minimum of -10mA current must flow through the base to drive -300mA of collector current.

The diagram below illustrates the relationship between base current and collector current.



BC327 Pinout

The BC327 features three pins designated as follows: 1: Emitter, 2: Base, and 3: Collector. The pinout of the BC327 is illustrated in the figure below.



These pins serve for external connections within the electronic circuit. A minute current variation at the base terminal results in a substantial current change across the other terminals. The base terminal is crucial in distinguishing between NPN and PNP transistors. In an NPN transistor, current flows through the base side when voltage is applied, while in a PNP transistor, no current flows through the base terminal when the transistor is turned ON.


BC327 Pin Configuration


Pin No. Pin Name Description
1 Collector (C) Current flows in through the collector terminal, representing the output terminal.
2 Base (B) Controls the current flow between the collector and emitter terminals. Input terminal.
3 Emitter (E) Current exits through the emitter terminal. Represents the ground or common terminal.


Features of BC327


PNP Bipolar Junction Transistor:

The BC327 belongs to the PNP-type transistor category, rendering it appropriate for scenarios demanding the utilization of PNP transistors.


Low Current Operation:

Tailored for efficient operation with low current inputs, the BC327 proves ideal for applications where current availability is restricted.


Low Voltage Ratings:

Equipped with low voltage ratings, the BC327 aligns with circuits necessitating low-voltage operation.


High Current Gain (hfe):

This transistor exhibits high current gain and ensures effective signal amplification, maintaining signal fidelity across various amplification circuits.


Low Power Dissipation:

Marked by low power dissipation, the BC327 minimizes energy loss, thereby contributing to the overall efficiency of electronic devices.


Amplification and Switching Applications:

With versatility in its applications, the BC327 finds common use in amplification and switching roles within electronic circuits.


Compact Form Factor:

Encased in a compact TO-92 package, the BC327 facilitates the design of space-efficient circuits, making it well-suited for applications with size constraints.



Its adaptability allows the BC327 to find utility across various electronic applications, adjusting to diverse circuit requirements.



Renowned for its reliability, the BC327 transistor ensures steadfast and consistent performance over time, augmenting the longevity of electronic devices.


BC327 Specifications


Parameter Value
Transistor Type PNP
Current - Collector (Ic) (Max) 800 mA
Voltage - Collector Emitter Breakdown (Max)
 45 V
Base-Emitter on Voltage -1.2V
Vce Saturation (Max) @ Ib, Ic
 700mV @ 50mA, 500mA
Current - Collector Cutoff (Max) 100nA
DC Current Gain (hFE) (Min) @ Ic, Vce 100 @ 100mA, 1V
Power - Max
 625 mW
Frequency - Transition
Operating Temperature
 -55°C ~ 150°C (TJ)
Package / Case


Absolute Maximum Ratings


Rating Symbol Value Unit
Collector−Emitter Voltage VCEO −45 Vdc
Collector−Emitter Voltage VCES −50  Vdc
Emitter−Base Voltage VEBO −5.0 Vdc
Total Power Dissipation @ TA = 25°C
Derate above TA = 25°C
PD 625
Total Power Dissipation @ TA = 25°C
Derate above TA = 25°C
PD 1.5
Operating and Storage Junction Temperature Range TJ, Tstg −55 to +150 °C


These represent stress thresholds critical to the success of your project. Ensure the ratings remain within the specified absolute limits to safeguard your components. Likewise, prolonged application of these ratings beyond the necessary duration may impact the device's reliability.


BC327 Equivalents/Alternatives

BC327 finds its counterparts in a spectrum of transistors with similar characteristics and functionalities in electronic components. These equivalents provide flexibility in choosing components for various applications. Let's delve into the details of each equivalent without explicitly emphasizing BC327.



A reliable alternative, 2N4403 complements BC327 seamlessly, showcasing comparable performance in transistor applications.



BC488 stands out as a viable option within the family of equivalents, offering compatibility and reliability akin to BC327.



BC638 emerges as a suitable substitute, boasting features that align with the functionality of BC327, ensuring a seamless integration into electronic circuits.



With characteristics akin to BC327, 2N4402 steps in as a parallel option, maintaining the intended performance in diverse electronic setups.



Offering a parallel functionality to BC327, 2N3702 establishes itself as a dependable equivalent, catering to various electronic applications.



Much like BC327, 2N3703 is an efficient alternative, maintaining performance standards across varied electronic scenarios.



BC486 enters the scene as a comparable substitute, ensuring a harmonious compatibility with BC327 in electronic designs.



Within the realm of BC327 equivalents, BC490 surfaces as a noteworthy option, providing a seamless transition in electronic applications.



Another member of the equivalent family, BC328, aligns itself with BC327, offering a consistent performance profile for electronic endeavors.


Complementary NPN transistor: BC337-25


The BC337-25 shares similar characteristics with BC327, making it an ideal choice for applications where both transistors work together. Its inherent properties ensure a smooth transition between the two, maintaining the integrity of the circuit design. Its versatile nature and performance characteristics, similar to BC327, position it as a valuable component for electronics professionals aiming to achieve optimal circuit functionality.


The array of BC327 equivalents outlined above presents a diversified palette for electronics professionals, allowing for flexibility and adaptability in circuit design without compromising performance.


BC327 CAD Model



How does the BC327 Transistor Work?

The BC327 Transistor functions as a versatile PNP transistor, where the primary charge carriers are holes. When the transistor's base is grounded, a leakage current initiates, reducing the depletion region at the base. This causes an increasing migration of electrons from the collector to the emitter, maintaining a continuous current flow through the circuit.

In the absence of current at the base in this PNP transistor, it is turned ON; conversely, when current flows through the base, the transistor is turned OFF.

The PNP operates similarly to an NPN transistor but in a reversed manner. The base still governs the significant current across the other terminal, but in this case, the current flows in the opposite direction—from emitter to collector. Unlike the NPN transistor, where electrons are emitted, the emitter of the PNP transistor emits holes, which the collector then collects.


Where to Use BC327?

Due to its 800mA collector current, the BC327 transistor proves versatile for driving a diverse range of loads in electronic applications. This includes high-power relays, transistors, LEDs, ICs, and more. With a maximum collector-emitter voltage of -45V, it adeptly manages load voltages below 45V. Additionally, boasting a collector dissipation of 625mW and a maximum DC gain of 630, it finds utility as an audio amplifier or in various signal amplification scenarios. Employing a -5V emitter-base voltage, the BC327 can serve as the output for microcontrollers, powering loads of up to 800mA—effectively driving motors, modules, sensors, and similar components.


How to Use BC327?

In contrast to MOSFETs, transistors operate as devices controlled by current, requiring the provision of the specified base current (in the case of the BC327 transistor, it's -10mA) to toggle between on and off states. As a PNP transistor, the BC327 conducts when connected to the ground and turns off when the base links to 5V.

The illustrated circuit demonstrates the transistor's behavior with and without applied base current.



Activating the transistor by grounding the base ensures it stays on unless the voltage surpasses 1.2V. Leaving the base floating may lead to false triggering, necessitating the inclusion of pullup resistors. In this instance, a 10K resistor pulls up the transistor's base.

In this application, the BC327 is a basic switching component, controlling a 12V motor as the load. The button triggers the transistor, and its removal leaves simple contacts. A 10KΩ resistor limits the current to the base, preventing voltage breaches, while a 2.1KΩ resistor regulates the current flowing from the base to the ground.


BC327 Circuits Examples


BC327 as an Amplifier


This compact audio amplifier delivers a power output of up to 250mW and finds application as the final stage audio amplifier in radio sets. The schematic is simple: a lone BC547 transistor governs a balanced power amplifier comprising BC337 and BC327. The total amplification, approximately 15x, is determined by R1, R3, and P1. The overall current consumption is 180mA, with an input sensitivity of 95mV. 




BC327 as a Switch


Upon closing the switch, the BC327's base is lowered to around 11.3V, drawing approximately 1.5mA from the transistor's base—sufficient base current for a 100mA load. The BC327's minimum hFE is 100, exceeding the 2N3906's minimum hFE. Q1 is configured in common emitter mode.

Closing the switch pulls the BC548's base almost to the ground, turning off the LED, as the BC548 operates in emitter follower mode.

Upon opening the switch, the BC327's base is raised to about 11.9V, turning off the BC327 and causing its collector to drop to 0V. Simultaneously, R2 and R4 provide a base current to Q2, turning on the LED.


BC327 Application

The BC327 transistor finds versatile applications in:

  • Signal amplification and switching.
  • Serving as the output for microcontrollers to drive loads.
  • Integration into audio amplifiers and various preamplification stages.
  • Driving loads under 800mA.
  • Implementing push-pull configuration circuits.
  • Usage in medium-speed switching and high-frequency amplifiers.
  • Providing ESD protection.
  • Safeguarding data lines.
  • Applications in PWM-driven circuits.
  • Serving as relay drivers.
  • Contributing to steering logic.
  • Protecting against inductive loads.
  • Serving in microphone preamplifiers.
  • Controlling LED dimmers or flashers.


BC327 Advantages

1. Advanced Process Technology:

The BC327 transistor leverages cutting-edge process technology, reflecting a commitment to innovation. This technological advancement ensures that the transistor operates with heightened efficiency, contributing to performance enhancements in electronic circuits.


2. Low Error Voltage:

One notable advantage of the BC327 is its low error voltage. This characteristic minimizes discrepancies in voltage levels, fostering precision in signal processing. Such accuracy is paramount in applications where even slight deviations can impact the functionality of electronic systems.


3. Fast Switching Speed:

BC327 boasts an impressive fast-switching speed, a crucial attribute in dynamic electronic environments. The ability to swiftly transition between states enhances the transistor's applicability in applications demanding rapid response times, such as high-frequency signal processing.


4. Full-Voltage Operation:

The BC327 excels in full-voltage operation, accommodating a wide, stable voltage range. This versatility makes it a reliable choice for diverse electronic circuits, allowing seamless integration into systems with varying voltage requirements.


5. High Power and Current Handling Capability:

A standout feature of the BC327 is its remarkable power and current handling capability. This advantage positions the transistor as a robust component capable of withstanding demanding conditions. Its high-power capability suits it for applications with substantial power and current loads.


BC327 Datasheet

Download BC327 Datasheet PDF.


What is the Difference between NPN and PNP Transistor?


NPN stands for Negative-Positive-Negative, and PNP stands for Positive-Negative-Positive. Let's delve into the differences between NPN and PNP transistors.

  • PNP transistors activate with a low signal, whereas NPN transistors activate with a high signal. In PNP transistors, the "P" signifies the polarity of the emitter terminal, and "N" signifies the polarity of the base terminal. In NPN transistors, "N" denotes the negatively charged coating of the material, while "P" denotes the positively charged layer.
  • Applying a positive voltage to the collector terminal induces a current flow from the collector to the emitter in an NPN transistor. Conversely, providing a positive voltage to the emitter terminal in a PNP transistor causes current to flow from the emitter to the collector.
  • PNP transistors offer the advantage of a lower turn-on voltage, making them well-suited for high-speed applications. On the other hand, NPN transistors boast a higher current-carrying capacity, rendering them ideal for use in low-power applications.


The key difference lies in their biasing and the polarity of the power supply for each type. We also have more information on the NPN transistor product to explore!


Final Words

The BC327 PNP transistor is a versatile electronic component notable for its impressive voltage tolerance and stability. These characteristics position it as a crucial element in various amplification and switching circuits. By comprehending its specifications, pin configuration, and applications, electronics enthusiasts gain the insights to harness its capabilities effectively.

Its elevated voltage tolerance and reliability designate the BC327 as a preferred choice in amplifiers, oscillators, and diverse consumer electronics. As technology progresses, the BC327 continues to explore new applications, reinforcing its pivotal role in the continually evolving field of electronic design.


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  • What type of transistor is BC327?

    Bipolar PNP transistor.

  • What is the function of BC327?

    The BC327 is suitable for driving loads up to 800mA and can handle load voltages up to 45V. It finds common applications in electronic circuits for both amplification and switching purposes.

  • What is the base current of BC327?


  • How do you get long-term performance with BC327 in a circuit?

    For optimal, long-term performance in your electronic applications with this transistor, it is advisable not to exceed a load current of 0.8A or 800mA, avoid load voltages exceeding -45V, always incorporate an appropriate base resistor with the transistor, refrain from storing or operating the transistor in temperatures below -55 degrees Celsius or above +150 degrees Celsius, and verify the pin configuration before integrating it into the circuit.

  • How do I know if my transistor is NPN or PNP?

    The only difference lies in the direction of the arrow on the emitter. In an NPN (on the left), it points outward, whereas in a PNP (on the right), it points inward.

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