How a semiconductor diode lets current pass one way, how it is used to convert alternating current to direct current by half-wave rectification, and comparing V–t graphs of battery d.c. and rectified a.c.
4 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Your phone charger turns the mains a.c. into the d.c. your phone battery needs. At the heart of it is a tiny one-way valve for current: the diode.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Conducts in the forward direction; blocks in the reverse direction.
Conversion of a.c. into d.c.
One diode in series with a resistor; only positive half-cycles pass.
Positive half-cycles separated by zero.
Constant voltage: flat V–t line.
A diode that emits light.
Current flows in the direction of the arrow.
Chargers, radios, electronic circuits.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Physics Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (13 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [13 marks]
A diode and a resistor are connected in series to a 120 V, 60 Hz a.c. supply.
(a) (a) State the property of a diode that makes it useful as a rectifier. [2]
(b) (b) Draw a circuit diagram of a half-wave rectifier. [3]
(c) (c) Sketch two V–t graphs: the input voltage and the output voltage across the resistor. [4]
(d) (d) Explain why the output is described as direct current. [2]
(e) (e) State one difference between the V–t graph of the output and that of a battery. [1]
(f) (f) State one use of a rectifier. [1]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.