Meaning and mechanism
Half-wave rectifiers utilize a single cycle, while full-wave rectifiers replace two cycles with an output in the same direction. There remains a time-dependent ripple in the output.
A smoothing capacitor charges when the voltage is high and supplies energy to the load between the peaks. The rate at which the output decreases during discharge is related to ripple.
Relationships and conditions
The rate of abnormal RC discharge decreases exponentially. When the capacitance is larger at the same load, there tends to be a smaller voltage drop between peaks.
The voltage drop of a real diode, as well as charging current and the power resistor, are omitted from the simple model. A large capacitor does not guarantee perfectly consistent output under all conditions.
What to observe in the simulation
Full-wave rectification uses both half-cycles, while the capacitor holds voltage between peaks.
Diode voltage drops, inrush current and source resistance are omitted. RC discharge uses an exact segment solution. Experiment on screen; do not reproduce this with real power supplies, outlets or high voltage.
Key relationships and symbols
Vout = |Vin| (full-wave) · C dV/dt = −V/R (off)
| Symbol | Meaning | Unit |
|---|---|---|
| C | Smoothing capacitance | F |
| R | Load resistance | Ω |
| Ripple | Residual variation in output voltage | V or a ratio |
Worked example
What is the output period for full-wave rectification of a 50 Hz input without smoothing?
10 ms
Common misconceptions
- Rectified radio waves and voltage regulation that maintains a constant voltage are not the same function.