Rectifier Output Calculator

The first practical rectifier was Thomas Edison's 1883 observation of one-way current flow through a vacuum-tube filament — "the Edison effect" — which John Ambrose Fleming turned into the vacuum-tube diode in 1904. Fleming's valve enabled AM radio detection and became the first electronic rectifier in mass production, followed by mercury-arc rectifiers for industrial DC supplies in the 1920s.

Solid-state rectification emerged with the 1920s development of copper-oxide (CuO) rectifiers by L.O. Grondahl at Union Switch & Signal, and selenium rectifiers in the 1930s. Both were clunky (low efficiency, huge stacks for a few amps) but replaced vacuum tubes in power supplies, battery chargers, and welders. Silicon P-N diodes arrived in 1954 (Bell Labs) and displaced selenium by the early 1970s — 10× the current density with a tenth the forward drop.

The bridge rectifier topology predates semiconductors — patented by Polish engineer Karol Pollak in 1895 as a mechanical rotary device. Graetz wrote it up for general use in 1897 (hence "Graetz bridge" in European literature). Full-wave center-tap topology came earlier still (1880s) but required a center-tapped transformer. Today virtually all line-frequency rectification uses four-diode bridge configurations, either as discrete diodes or as single-part bridge modules (KBPC, GBPC series).

Enter transformer secondary RMS voltage, line frequency, rectifier topology (half-wave, full-wave bridge, or center-tap), load current, bulk capacitance, and diode forward drop Vf (0.7 V silicon, 0.3 V Schottky — count one Vf for half-wave, two Vf for bridge). The tool returns peak DC (Vpk = √2·Vrms − n·Vf), peak-to-peak ripple Vr ≈ I/(f·C), average DC, and ripple frequency.

Rule of thumb for bulk cap sizing: 2000-3000 µF per amp of load current at 60 Hz full-wave gives ~2 V ripple — plenty for a downstream linear regulator to clean up. For offline rectifiers (120/230 VAC direct to bulk cap), add NTC inrush limiting or a precharge relay; cold bulk caps can draw 30-60× steady-state current on the first half-cycle. Everything runs client-side; no values leave your browser.