Lesson Notes By Weeks and Term v4 - SHS 1
ANALOGUE ELECTRONICS
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ANALOGUE ELECTRONICS
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Subject: Physics
Class: SHS 1
Term: 2nd Term
Week: 19
Grade code: 1.3.3.LI.3
Strand code: 3
Sub-strand code: 3
Content standard code: 1.3.3.CS.2
Indicator code: 1.3.3.LI.3
Theme: ELECTRIC FIELD, MAGNETIC FIELD AND ELECTRONICS
Subtheme: ANALOGUE ELECTRONICS
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Good morning, class. Today, we are diving into a very practical part of physics called Analogue Electronics. Look around you. From the mobile phone in your pocket to the sound system at church or the mosque, to the remote control for your TV at home, we are surrounded by devices that make our lives easier. Many of these devices work because of special components called transducers. A transducer is simply a device that changes one form of energy into another. Understanding them helps us understand how most of the gadgets we use every day actually work. This knowledge is for everyone, regardless of your gender or background.
A. What is a Transducer?
A transducer is any device that converts energy from one form to another. The energy conversion is the most important part. For example, a light bulb is a transducer because it converts electrical energy into light energy and heat energy.
In electronics, we are often interested in converting signals between the physical world (like sound, light, or movement) and the electrical world. B. The Microphone (Dynamic Type)
A microphone is a transducer that converts sound energy into electrical energy. Think of a pastor preaching at church; the microphone "catches" his voice and turns it into an electrical signal. Energy Conversion: Sound Energy (Mechanical Wave) → Electrical Energy (Audio Signal) Key Parts: Diaphragm: A thin, flexible sheet that vibrates when sound waves hit it. Voice Coil: A small coil of wire attached to the back of the diaphragm. Permanent Magnet: A magnet that creates a steady magnetic field. How it Works (Step-by-Step): Sound Waves Arrive: When someone speaks or sings into the microphone, the sound waves (which are vibrations in the air) travel and hit the diaphragm. Diaphragm Vibrates: The pressure changes from the sound waves cause the diaphragm to vibrate back and forth. Coil Moves: Since the voice coil is attached to the diaphragm, it also moves back and forth within the magnetic field of the permanent magnet. Current is Induced: According to the principle of electromagnetic induction (Faraday's Law), whenever a conductor (the coil) cuts through magnetic field lines, a voltage is induced across its ends, causing a small electrical current to flow. Signal is Created: The vibration of the coil perfectly matches the pattern of the original sound wave. Therefore, the electrical current produced is an electrical copy, or an "analogue," of the sound. This is called an audio signal.