Lesson Notes By Weeks and Term v4 - SHS 2

Lesson Video

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Performance objectives

• Define capacitance.
• Identify factors affecting the capacitance of a parallel plate capacitor.
• Calculate capacitance using the formula C = εA/d.
• Relate capacitance to real-life applications in Ghana.

Lesson summary

Welcome, future engineers and scientists! Today, we are exploring a fundamental component in almost every electronic device you use: the capacitor. Think about your phone, the radio in your house, the ceiling fan that cools you down, or even the power supply from the ECG that keeps our lights on. All these devices rely on capacitors to function properly. A capacitor is like a small, temporary battery that can store and release electrical energy very quickly. In this lesson, we will learn what makes a capacitor good at its job by investigating the factors that determine its ability to store charge, a property we call capacitance.

Lesson notes

2.1. What is a Capacitor and Capacitance?

Imagine you have a bucket to fetch water. The size of the bucket determines how much water you can store in it. In electronics, a capacitor is like a bucket for storing electric charge. Capacitor: A device composed of two conductive plates separated by an insulator (or a vacuum), designed to store electrical energy in an electric field. Capacitance (C): This is the measure of a capacitor's ability to store electric charge. A capacitor has a large capacitance if it can store a large amount of charge for a given voltage.

Mathematically, capacitance is the ratio of the charge (Q) stored on one plate to the potential difference (V) between the plates.

Formula: `C = Q / V`

Evaluation guide

• Determine the capacitance of a parallel plate capacitor.
• Talk for Learning: Use the factors that affect the capacitance that affect parallel plate capacitor
• i.e., the area of the plate, the permittivity of the dielectric material and the distance of separation
• between the plates.