2N5551 Amplifier PNP Transistor

2N5551 Amplifier PNP TransistorThe 2N5551 is an NPN bipolar junction transistor designed for high-voltage and low-to-medium current applications. It supports a collector-emitter voltage of 160 V and a collector current of 600 mA, making it ideal for audio amplification, analog signal stages, and general-purpose switching tasks.You can drive it into conduction by applying a base-emitter voltage of ~0.7 V, allowing current to flow from collector to emitter. When you remove the base current, the transistor stops conducting, which makes it highly reliable for logic control and analog interfacing.This transistor complements the PNP 2N5401, making the pair useful in push-pull amplifiers and symmetrical designs. Designers often pair the 2N5551 with its PNP complement, the 2N5401, to form push-pull amplifier stages, symmetric analog stages, or complementary switching pairs. This pairing enhances circuit efficiency and simplifies designs that require both sourcing and sinking current paths. Pin Configuration (TO-92 Package)PinNameDescription1EmitterCurrent flows out2BaseControls switching or gain3CollectorCurrent flows inKey FeaturesHandles up to 160 V collector-emitterSupports 600 mA collector currentProvides DC gain (hFE) of 100–300Performs well in analog and low-frequency stagesComes in a compact TO-92 plastic packageSwitches moderately fast (~100 MHz fT)Works as an NPN counterpart to 2N5401ApplicationsAmplify signals in audio and analog circuits.Switch high-voltage loads in control systems.Build discrete transistor amplifiers.Drive display panels, relays, and LEDs.Design voltage-level shifting or interfacing stages.Implement active filters or gain stages.Use in preamp or postamp stages for audio.Construct push-pull amplifier stages with 2N5401.Use in power regulators and biasing networks.Support education for high-voltage transistor behavior.Specifications TableParameterValueTransistor TypeNPNMax Collector Current600 mAMax Collector-Emitter Voltage160 VMax Collector-Base Voltage180 VMax Emitter-Base Voltage6 VDC Current Gain (hFE)100–300Max Power Dissipation625 mWTransition Frequency (fT)~100 MHzCollector Saturation Voltage~0.3–0.75 VPackage TypeTO-92             ‘Operating Temperature-55 to 150 °C