BD135 Bipolar Medium Power NPN Transistor – TO-126 Package

The BD135 is a silicon NPN medium-power bipolar junction transistor (BJT) designed for linear amplification and switching applications. With its high current capability, good voltage rating, and TO-126 package for improved heat dissipation, it is widely used in audio amplifier driver stages, power control circuits, voltage regulators, relay drivers, and industrial electronic applications. The BD135 is the complementary NPN counterpart of the BD136 PNP transistor.

Key Features -

• Medium-power NPN transistor

• Silicon transistor technology

• Suitable for linear amplification and switching applications

• High collector current capability

• TO-126 package with heatsink mounting provision

• Good thermal stability and reliability

• Complementary pair with BD136, BD138, and BD140 series

Specifications -

• Product type - Bipolar Junction Transistor (BJT)

• Part number - BD135

• Transistor polarity - NPN

• Technology - Silicon

• Package type - TO-126 (SOT-32)

• Mounting type - Through Hole

• Number of pins - 3

• Collector-Emitter Voltage (VCEO) - 45V

• Collector-Base Voltage (VCBO) - 45V

• Emitter-Base Voltage (VEBO) - 5V

• Maximum Collector Current (IC) - 1.5A

• Power Dissipation - Up to 12.5W (with proper heatsinking)

• DC Current Gain (hFE) - 40 to 250 (depending on variant)

• Junction Temperature - Up to 150°C

• Operating Temperature Range - -55°C to +150°C

Applications -

• Audio amplifier driver stages

• Medium-power amplifier circuits

• Power supply circuits

• Voltage regulator applications

• Relay and solenoid driver circuits

• Motor control circuits

• Industrial control systems

• Educational and DIY electronics projects