A transistor having α = 0.90 is used in a common base amplifier....
The expression of voltage gain is as follows:
AV = αRL / Re
Given: α = 0.90, RL = 5.0 kΩ = 5000 Ω, Re = 50 Ω
AV = 0.90 × 5000 / 50
AV = 90
A transistor having α = 0.90 is used in a common base amplifier....
Three layers of semiconductor material (n-type, p-type, n-type), is called a bipolar junction transistor (BJT). It consists of two pn junctions, hence the name bipolar. The three layers are referred to as the emitter, base, and collector.
The BJT operates in two modes: the active mode and the saturation mode. In the active mode, the transistor acts as an amplifier, where a small input current or voltage controls a larger output current or voltage. In the saturation mode, the transistor acts as a switch, where a small input current or voltage turns on the transistor to allow a larger current to flow from the collector to the emitter.
The BJT has three terminals: the emitter, base, and collector. The emitter is heavily doped with impurities to increase its conductivity. The base is lightly doped and acts as a control terminal. The collector is moderately doped and collects the majority of the current flowing through the transistor.
When a small current flows into the base-emitter junction (forward bias), it allows a larger current to flow from the collector to the emitter. This is known as the current amplification factor or beta (β) of the transistor. The beta value determines the amplification capability of the transistor.
Overall, the BJT is a versatile electronic component that is widely used in amplifiers, switches, and various other electronic circuits. Its ability to amplify and switch signals makes it an essential component in modern electronics.