Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Identify the components of a smoother/filter circuit and their functions.
• Design a basic smoother/filter circuit using a capacitor.
• Analyze the effect of capacitor values on the circuit's performance.
• Evaluate the importance of these circuits in electronic devices.

Lesson summary

In our daily lives in Ghana, we use countless electronic gadgets – our mobile phones, radios, laptops, and TVs. All these devices need a steady, constant Direct Current (DC) to work properly. However, the power we get from the Electricity Company of Ghana (ECG) is Alternating Current (AC). A device like your phone charger must convert this AC into DC. The first step is rectification, but this creates a "bumpy" or *pulsating* DC, which is not good enough. Today, we will learn about the crucial next step: smoothing. We will learn how a simple component, the capacitor, can act as a filter to "smooth out" this bumpy DC, making it suitable for our sensitive electronics.

Lesson notes

2.1 The Problem: Pulsating DC from a Rectifier

Recall that a rectifier circuit (using diodes) converts AC into DC. Half-Wave Rectifier: Allows only one half of the AC cycle to pass, blocking the other half. Full-Wave Rectifier: Inverts the negative half of the AC cycle, so both halves contribute to the output.

The output of these rectifiers is not a smooth, flat line like the DC from a battery. It is Pulsating DC.

Waveform Diagrams:

Evaluation guide

• Design a smoother/filter circuit using capacitor.
• Collaborative learning: Using simulatio ns and multimedia, let learners watch a
• video/simulation of how a smoother/filter circuit is designed.
• Encourage the appreciation and valuing of the skills and abilities of individuals from diverse