Diode Rectifier Circuit
PhysicsElectricity & CircuitsAges 16–17
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Electricity & Circuits
A diode conducts in only one direction, turning an alternating voltage into a bumpy direct voltage. Compare half-wave rectification with full-wave rectification, then add a filter capacitor and change its capacitance to see the ripple shrink — just how a phone charger's power supply works.
Lesson: Introduction to Electronics
What it shows
A diode lets current flow in one direction only, which makes it possible to turn alternating voltage into direct voltage. Here a 50 Hz supply of about 12 V peak feeds either one diode (half-wave), which blocks every negative half-cycle, or a bridge of four diodes (full-wave), which flips the negative half-cycles to positive and doubles the ripple frequency to 100 Hz. Each conducting diode drops about 0.7 V. A filter capacitor charges to the peak and discharges through the load between peaks; when the time constant RC is much longer than the gap between peaks, the output is almost steady DC.
How to use
Start with Half-wave (one diode) and no filter, and compare the input trace with the voltage across the load. Change Rectifier type to full-wave and note what happens to the gaps and to the average voltage. Then turn on Filter capacitor and raise Filter capacitance while watching the ripple value; finally lower Load resistance to draw more current and see the ripple grow again.
Parameters you can change
- Rectifier type Half-wave (one diode), Full-wave (four-diode bridge)
- Filter capacitor
- Filter capacitance 10–2000 µF
- Load resistance 20–2000 Ω
Questions to explore
- Why does full-wave rectification give a smoother output voltage than half-wave rectification?
- How does increasing the filter capacitance affect the ripple of the output voltage?
- With the same capacitor, why does a smaller load resistance make the ripple larger?
