BD139 Discrete Semiconductor Products

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Bipolar junction transistors (BJTs) are widely used active components in the field of electronics. Among them, the BD139 has certain advantages comparing to other transistors. In this article, the application of BD139 and its working principle are discussed.

The BD139 transistor is a single-package, NPN transistor with a plastic casing in the TO-126 type. It has a high current gain, making it a great choice for amplifying or switching applications. The maximum ratings of the transistor are a collector current of 11 A, collector-emitter voltage of 75 V and emitter-base voltage of 5 V. With a power dissipation rate of 25 W and a collector-emitter breakdown voltage of 90 V, the BD139 has the capability to handle high voltages, making it suitable for many different scenarios.

The main application fields of the BD139 transistor are switching, linear and audio applications. In switching applications, the transistor is used as an electronic switch to control the flow of current in electronic circuits. As for linear applications, it can provide acceleration and deceleration of transistor current when used with an operational amplifier. It is also very suitable for audio applications, as it can be used as a pre-amplifier or an audio amplifier.

The working principle of the BD139 is based on the fact that it has three layers: base, collector and emitter. When a positive voltage is applied to the base, a current will flow from the collector to the emitter. The current flowing through the collector-emitter junction is known as the collector current. The current gain of the BD139 is known as its β or HFE, which is the ratio of collector current to base current. This current gain can be adjusted to control the amount of current flowing through the transistor.

To summarize, the BD139 is a single-package, NPN transistor suitable for switching, linear and audio applications. It has a high current gain and a maximum ratings of collector current of 11A, collector-emitter voltage of 75V, emitter-base voltage of 5V, power dissipation rate of 25W and collector-emitter breakdown voltage of 90V. The working principle of the BD139 is based on the three layers: base, collector and emitter. When a positive voltage is applied to the base, a current flow from the collector to the emitter. The current gain of the BD139 is the ratio of collector current to base current.

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