Bridge rectifier calculator
120 V RMS through 0.7 V silicon diodes gives a DC peak of 120 times the square root of 2, minus two diode drops. Enter the RMS voltage and one diode's drop to get the DC peak, the AC peak and the unfiltered average. Free in your browser.
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- Your data stays on your device
Run — free
Worked example
- Rms voltage
- 120
- Diode drop
- 0.7
- Peak voltage
- 169.7056274848
- Dc voltage
- 168.3056274848
- Average voltage
- 107.1466902575
A full-wave bridge rectifier converts an alternating RMS source into unidirectional DC by routing current through four diodes so both half-cycles of the AC waveform contribute to the load. At any instant two diodes conduct in series, which is why the useful peak at the output is the AC peak minus twice the forward drop of a single diode. This calculator accepts the AC RMS input voltage and one diode forward voltage, computes the peak as RMS times the square root of two, subtracts two diode drops, and returns the rectified DC voltage together with the peak, the unfiltered full-wave average, and the formula used. Silicon diodes are typically about zero point seven volts; Schottky parts are lower.
What a full-wave bridge does and how Vdc is formed
A single-phase full-wave bridge rectifier uses four diodes in a diamond so the load always sees the same polarity. During the positive half-cycle of the AC source, one diagonal pair conducts; during the negative half-cycle the other pair conducts. In both cases two semiconductor junctions sit in series with the load, which is why a single diode drop is never enough to describe the output.
The AC source is almost always specified as an RMS voltage Vrms. The corresponding peak of a sinusoid is Vrms times the square root of two. Subtracting two forward drops Vf yields the first-order DC peak: Vdc equals square-root-of-two times Vrms minus two Vf.
That identity is the model this calculator implements. Ideal diodes correspond to Vf of zero, so the DC peak collapses to the AC peak. Silicon power diodes typically sit near zero point seven volts; Schottky parts are lower; series strings and silicon-carbide devices are higher.
Transformer winding resistance, leakage inductance, reverse recovery, and temperature coefficients are outside this voltage identity: treat the result as the textbook first estimate you check before a SPICE run, not as a complete converter design.
When a quick bridge estimate helps
Power-electronics homework and lab reports need a deterministic oracle for Vdc from a stated RMS secondary and a datasheet diode drop, so a sign error on the two-diode path is caught before the student sizes a filter capacitor. Bench technicians checking a wall-adapter secondary, a small transformer, or a mains-to-DC front end can convert a measured RMS into the expected unloaded peak after two silicon or Schottky drops without opening a spreadsheet.
Catalog pages that rank for bridge rectifier calculator benefit from a live tool whose free browser path matches the automation path byte-for-byte. Prefer this landing when you already have an RMS figure and a single-diode Vf and you want the first-order peak and the unfiltered average; convert peak-specified sources to RMS first, and convert millivolts to volts if your datasheet uses that prefix. The model is not a replacement for a load-and-ripple calculation, a centre-tap two-diode comparison, a three-phase bridge, or a regulated supply.
Failed validation does not consume balance.
What you can do with it
Homework and lab rectifier checks
Convert a textbook AC RMS secondary and a silicon or Schottky Vf into the expected DC peak and unfiltered average before sizing a filter capacitor.
Adapter and transformer secondary screening
From a measured RMS winding, estimate the unloaded bridge peak after two diode drops when checking a wall adapter or a small power transformer.
FAQ
Why are two diode drops subtracted instead of one?
In a single-phase bridge, two diodes conduct on every half-cycle. The load path always includes two forward junctions, so the DC peak is the AC peak minus 2·Vf, not minus a single Vf as in a half-wave rectifier.
What happens if the RMS voltage or the diode drop is negative?
Negative RMS or Vf is not a physical bridge input, and those failures are not billed. Zero Vf is allowed and means ideal diodes.
Does this include capacitor ripple or load current?
Ripple, transformer resistance, and load current are out of scope; use the peak as the usual unloaded or heavily filtered estimate, then apply your own ΔV = I/(fC) if needed.
What diode drop should I enter?
The forward voltage of a single diode: about 0.7 V for silicon, less for Schottky parts, more for series strings or silicon-carbide devices. Enter 0 to model ideal diodes, in which case the DC peak equals the AC peak.
What if the two diode drops are larger than the AC peak?
Then the diodes never conduct and no DC appears, so the calculation is refused instead of showing a negative voltage that a real bridge cannot produce. A zero RMS input with a positive drop is refused for the same reason.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/phys/bridge-rectifier \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"rms_voltage":120,"diode_drop":0.7}'const res = await fetch("https://api.kit.forhosting.com/phys/bridge-rectifier", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"rms_voltage": 120,
"diode_drop": 0.7
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/phys/bridge-rectifier",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"rms_voltage": 120,
"diode_drop": 0.7
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/phys/bridge-rectifier", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"rms_voltage":120,"diode_drop":0.7}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"rms_voltage":120,"diode_drop":0.7}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/phys/bridge-rectifier", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"rms_voltage": 120,
"diode_drop": 0.7
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "phys.bridge_rectifier",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Negative RMS or diode-drop values fail with invalid_input and are not billed.
What a full-wave bridge does and how Vdc is formed
With a large reservoir capacitor the filtered output sits near this peak, minus a small ripple that depends on load current and capacitance, which this endpoint does not model. Without a capacitor the load sees a full-wave rectified sinusoid whose amplitude is that same reduced peak and whose average is two over pi times the peak; that average is returned as average_voltage. If twice Vf exceeds the AC peak, the diodes never forward-bias, no DC appears, and the request is rejected rather than returning a negative voltage that a real bridge cannot produce.
Input contract, response shape, and error behaviour
Negative RMS or diode drop is rejected because a source polarity or a negative barrier does not describe a physical bridge; those failures are not billed. Zero diode drop is valid and means ideal diodes. Zero RMS with a positive drop cannot forward-bias the bridge, so it is rejected the same way as any case where two drops exceed the AC peak. Example: one hundred twenty volts RMS and zero point seven volts per diode yields a peak of one hundred twenty times the square root of two, a DC peak after one point four volts of drop, and the matching full-wave average. POST a JSON body with two required finite numbers: rms_voltage, the AC RMS source in volts, and diode_drop, the forward voltage of one diode in volts. Each field may arrive as a JSON number or as a numeric string; aliases vin, vac, v_rms, ac_voltage, and input_voltage are accepted for rms_voltage, and vf, v_f, forward_voltage, v_diode, and diode_voltage for diode_drop, so spreadsheets and typed forms can reuse the same contract. Missing fields, empty strings, and non-finite values fail with invalid_input naming the field. On success the body echoes the rounded rms_voltage and diode_drop, then reports peak_voltage as RMS times the square root of two, dc_voltage as that peak minus two drops, average_voltage as two over pi times dc_voltage, a formula string restating the identity, and method full_wave_bridge. Pair the response with your own ripple estimate if you have load current and filter capacitance; this endpoint solves the voltage identity only and does not emit plots, transformer sizing, or heatsink advice. A successful API call costs $0.002.
Where a bridge-rectifier voltage API earns its keep
Keep requests inside the documented magnitude ceiling, pin the rounded dc_voltage in tests, and you get reproducible rectifier arithmetic for homework, LMS plugins, and edge workers without standing up a circuit simulator of your own.
Integration use cases
CI fixtures for DC-rail assertions
Call the same deterministic solve from tests so a known AC RMS fixture always maps to the same dc_voltage without a circuit simulator.
Technical questions
How is the DC voltage of a full-wave bridge rectifier calculated?
Send finite non-negative rms_voltage (AC RMS in volts) and diode_drop (one diode Vf in volts). The API returns Vdc = √2 · Vrms − 2 · Vf as dc_voltage, plus the AC peak and the unfiltered average 2·Vdc/π.
What does the bridge rectifier calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.