BC556 PNP
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The BC556 is a very common, general-purpose PNP bipolar junction transistor (BJT), often used for small-signal amplification and switching. It is the PNP complement to the BC546 to BC550 series.
💡 BC556 Product Detail
Core Function and Type
Type:PNP Bipolar Junction Transistor (BJT).
Function: It is primarily used for small-signal amplification and low-current switching applications. Since it's a PNP type, it is generally used for high side switching, controlling a load connected to the positive supply rail.
Operating Principle: A small negative voltage/current applied to the Base (relative to the Emitter) allows current to flow from the Emitter to the Collector.
Key Specifications
| Parameter | Typical Value | Description |
| Collector Current (I_C) | -100mA | The maximum continuous current it can switch. |
| Collector-Emitter Voltage (V_CE) | -65V | The maximum voltage it can withstand. (Note: BC556 has a higher voltage rating than BC557/BC558). |
| DC Current Gain (h_FE) | 110 to 800 | The high ratio of Collector current to Base current ($\beta$). |
| Power Dissipation (P_D) | 500mW | the maximum power it can safely dissipate. |
Note: For PNP transistors, voltages and currents are often specified as negative relative to the Emitter.
Package and Pinout
Package: The BC556 is typically supplied in the plastic TO-92 through-hole package.
Pinout: When viewed from the flat side, the standard European pinout is:
Collector
Base
Emitter
Common Applications
The BC556 is widely utilized in various electronic designs:
Small-Signal Amplification: Used in pre-amplifier stages for general signal boosting.
High-Side Switching: Ideal for controlling small loads (like LEDs or low-current indicators) that are connected to the ground side.
Audio Circuits: Employed in various stages of audio equipment.
Complementary Circuits: Often paired with an NPN transistor (like the BC546 or BC547) in complementary push-pull stages or general switching applications.