A bipolar transistor or a BJT is a 3 terminal semiconductor device which is able to amplify or switch small signal input voltages and currents to significantly larger output signal voltages and currents. How Bipolar Junction Transistor BJTs Evolved During 1904–1947, the vacuum tube was unquestionably the electronic device of great curiosity and growth. In 1904, […]
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Understanding Common Base Configuration in BJTs
In this section we are going to analyze BJT common-base configuration, and learn regarding its driving point characteristics, reverse saturation current, base to emitter voltage and evaluate the parameters through a practical solved example. In the later parts we will also analyze how to configure a common-base amplifier circuit Introduction The symbols and annotations utilized […]
Common Emitter Amplifier – Characteristics, Biasing, Solved Examples
This configuration is known as common-emitter configuration because here the emitter is used as the common negative terminal for the input base signal and the output load. In other words, the emitter terminal becomes the reference terminal to both the input and output stages (meaning common to both the base and collector terminals). Common emitter […]
What is beta (β) in BJTs
In bipolar junction transistors the factor that determines the sensitivity level of the device to base current, and the amplification level at its collector is called beta or the hFE. This also determines the gain of the device. In other words, if the BJT uses relatively higher current to switch its collector load optimally then […]
Field-Effect Transistors (FET)
The field-effect transistor (FET) is an electronic device in which an electric field is used to regulate the flow of current. To implement this a potential difference is applied across the gate and source terminals of the device, which alters the conductivity between the drain and source terminals causing a controlled current to flow across […]
Transistor Common Collector
A BJT common collector amplifier is a circuit in which the collector and the base of the BJT share a common input supply, hence the name common collector. In our previous articles we have learned the other two transistor configurations, namely the common-base and the common-emitter. In this article I have explained the third and […]