Lesson Notes By Weeks and Term v4 - SHS 3
APPLICATIONS OF ELECTRONICS
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APPLICATIONS OF ELECTRONICS
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Subject: Physics
Class: SHS 3
Term: 2nd Term
Week: 16
Grade code: 3.3.4.LI.2
Strand code: 3
Sub-strand code: 4
Content standard code: 3.3.4.CS.2
Indicator code: 3.3.4.LI.2
Theme: ELECTRIC FIELD, MAGNETIC FIELD AND ELECTRONICS
Subtheme: APPLICATIONS OF ELECTRONICS
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Welcome, students! Today, we are exploring one of the most exciting and practical topics in electronics: designing an amplifier. Think about the last time you were at a church service, a school assembly, or even listened to music on a loudspeaker. The sound you heard started as a tiny, weak electrical signal from a microphone or a phone. How did it become powerful enough to fill the entire room? The answer is an amplifier. An amplifier takes a weak signal and makes it stronger.
Part 1: The Basics of Amplification
What is an Amplifier? An amplifier is an electronic circuit that increases the power, voltage, or current of a signal. It uses a small amount of energy from a power supply (like a battery or DC source) to control a larger amount of energy, creating a magnified version of the input signal at the output.
The NPN Transistor as an Amplifier We have already learned that a transistor has three terminals: the Base (B), the Collector (C), and the Emitter (E). The magic of a transistor in amplifier mode is that a very small current flowing into the base (Base Current, `Ib`) can control a much larger current flowing from the collector to the emitter (Collector Current, `Ic`). This relationship is defined by the transistor's DC current gain, called Beta (β).
`Ic = β * Ib`