Full Bridge Rectifier

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A full-bridge (Graetz) rectifier that converts AC to DC with four diodes.

Full-bridge (Graetz) rectifier: four diodes steer both halves of a 120 V, 60 Hz AC source into a 100 μF reservoir and a 1 kΩ load. Both AC polarities reach $V_{\mathrm{dc}}$ with the same sign.

The four-diode bridge steers both halves of the AC waveform to the load with the same polarity, so the unfiltered output ripples at twice the line frequency — easier to smooth than a half-wave stage. A reservoir capacitor filters the result into a steadier DC voltage, and the plot compares the AC input with the rectified output.

On each half-cycle one diagonal pair (D₁/D₄ or D₂/D₃) conducts, so the load always sees the same polarity and the raw output pulses at 120 Hz — twice the 60 Hz line, and half the gap the half-wave circuit had to bridge. With τ = RC = 1 kΩ × 100 μF = 100 ms far longer than the 8.3 ms between pulses, the 100 μF cap barely droops: V_dc holds close to the 120 V peak with only slight ripple. The run steps at 1 µs over 0.1 s (six line cycles). Compare the smoothness here to the half-wave sample to see why bridges dominate real supplies.