Half Bridge Rectifier

Open in app →

A half-wave rectifier that turns an AC source into a rough DC level.

Half-wave rectifier: a single diode passes the positive half-cycles of a 10 V, 60 Hz AC source into a 100 μF reservoir capacitor and a 200 Ω load. $V_{\mathrm{ac}}$ is the source, $V_{\mathrm{dc}}$ the smoothed output.

A single diode passes only the positive half of each AC cycle, and a reservoir capacitor holds the output up between peaks while the load resistor slowly discharges it — the balance that sets the output ripple. The scope overlays the AC input against the rectified, smoothed output so the conduction gaps and ripple are easy to spot.

Each positive peak recharges the capacitor to roughly the 10 V peak; for the rest of the 16.7 ms line period (60 Hz) the diode is reverse-biased and the load drains the cap with time constant τ = RC = 200 Ω × 100 μF = 20 ms. Because τ is only a little longer than the period, the output sags visibly between peaks — that sawtooth sag is the ripple. The run uses a 2 µs step over 50 ms (three line cycles). Enlarge the capacitor to flatten the ripple, or shrink the load resistance to make it worse.