Junction Transistor
Chapter Name : Semiconductor Electronics: Materials, Devices And Simple Circuits |
Sub Topic Code : 101_12_14_09_09 |
Topic Name : Junction Transistor |
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Sub Topic Name : Transistor As A Device-As A Switch |
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Introduction
A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power.
Pre-Requisites:
Transistor
Activity:
Silicon (Si) is the most widely used material in semiconductor devices.
Real Life Question:
What are transistors?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Transistor | A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| microprocessors | All transistor types can be used as the building blocks of logic gates, which are fundamental in the design of digital circuits. Transistors act as on-off switches; in the MOSFET, for instance, the voltage applied to the gate determines whether the switch is on or off. |
Real life uses :
Building circuits.
Places to visit :
Digital circuits.
Practical examples around us
| Examples | Explainations |
|---|---|
| Solar Cell | Solar cells are typically illuminated with sunlight and are intended to convert the solar energy into electrical energy. |
What you learn in Theory:
When used as an AC signal amplifier, the transistors Base biasing voltage is applied in such a way that it always operates within its "active" region, that is the linear part of the output characteristics curves are used. However, both the NPN & PNP type bipolar transistors can be made to operate as "ON/OFF" type solid state switches by biasing the transistors base differently to that of a signal amplifier.
What you learn in Practice:
If the circuit uses the Bipolar Transistor as a Switch, then the biasing of the transistor, either NPN or PNP is arranged to operate the transistor at both sides of the “I-V" characteristics curves we have seen previously.