← Electronics syllabus

SingaporeElectronics

Electronic Components

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does a capacitor store electric charge, and what does its capacitance tell us about how much it can store?

Describe a capacitor as a charge-storing component, define capacitance, and apply the relationship between charge, capacitance and voltage
A focused answer to the O-Level Electronics outcome on capacitors. How a capacitor stores charge, the definition of capacitance, the Q equals CV relationship, and charging and discharging.
8 min answer →

Why does a diode let current pass in one direction only, and how is that used to turn alternating current into direct current?

Describe the diode as a one-way component, state its forward voltage, and explain half-wave rectification of an alternating supply
A focused answer to the O-Level Electronics outcome on diodes. Forward and reverse bias, the forward voltage drop, half-wave rectification, and smoothing with a capacitor.
8 min answer →

How does an LED produce light, and why does it always need a series resistor to work safely?

Describe the LED as a light-emitting one-way component and calculate the series resistor needed to set a safe LED current
A focused answer to the O-Level Electronics outcome on LEDs. How an LED emits light, its forward voltage, why it needs a series resistor, and the calculation to size that resistor.
8 min answer →

What does a resistor do in a circuit, and how do we read its value from the coloured bands printed on it?

Describe the function and types of resistor, read the four-band resistor colour code, and choose a resistor value
A focused answer to the O-Level Electronics outcome on resistors. Fixed and variable types, the function of a resistor, and reading the four-band colour code including tolerance.
8 min answer →

How can a tiny current at one terminal of a transistor control a much larger current through it?

Describe the bipolar transistor, name its three terminals, and explain how a small base current controls a larger collector current
A focused answer to the O-Level Electronics outcome on the bipolar transistor. The base, collector and emitter, current control and gain, and the transistor used as a switch.
8 min answer →