Project – BD140 PNP Transistor (TO-126)

The BD140 is a medium-power PNP bipolar transistor from Fairchild that is particularly suited to medium power switching and amplification applications. It comes in a TO-126 package which makes heatsinking possible, further increasing the power handling capacity.

Features and Specifications

• 80V collector-emitter breakdown
• 1.5A continuous collector current
• Gain of between 63 and 250
• 1.25W power dissipation

The BD140 is a PNP bipolar transistor that can handle 80V and currents of up to 1.5A. It can be used for medium-power switching and amplifications.

It comes in a TO-126 case which has a screw hole enabling easier mounting to heatsinks, increasing the power dissipation capability.

Between 10 and 100mA, the gain curve is at its flattest, dropping off rapidly after 500mA. This means that to switch high collector currents, high base currents are needed. The saturation voltage is around 50mV, leading to low power dissipation and higher efficiency for switching loads.

Applications

• General purpose switching and amplification
• Audio amplifiers
• SMPS