BD139 NPN Transistor 80V 1.5A

This BD139 NPN bipolar transistor designed explicitly for use in general-purpose low power silicon NPN bipolar junction transistors. The BD139 has a very low saturation voltage and excellent high gain performance. Within the operating range, BD139 is available as a three terminal NPN device. The base current IB determines the collector current IC. For a given collector emitter voltage VCE, every change in the base current causes an amplified change in the collector current.

Transistors are the most important component in an electrical circuit. An NPN transistor is made up of two pieces of P-type silicon (the base) sandwiched between two pieces of N-type silicon (the collector and emitter). These transistors were created with the sole purpose of passing electrons from the emitter to the collector (so conventional current flows from collector to emitter). The emitter “emits” electrons into the base, and the quantity of electrons the emitter emits is controlled by the base. These electrons mix with the holes in the base and are delivered to the collector. The collector “collects” the majority of the electrons released and transmits them to the next portion of the circuit.

The purpose of the NPN transistor is to amplify weak signals that enter the base and create powerful amplify signals at the collector end. The travel of an electron in an NPN transistor is from the emitter to the collector area, resulting in current in the transistor. Because the bulk of charge carriers in such transistors are electrons, which have a higher mobility than holes, they are commonly utilised in circuits. The emitter, collector, and base of an NPN transistor are the three terminals. The centre part of an NPN transistor is weakly doped, and it is the most critical factor in the transistor’s operation. Meanwhile, the emitter was little doped, whereas the collector was extensively doped.