Documentation sections

Audio Transformer Turns Ratio

POSThttps://rftools.io/api/py/v1/calculate

Slug audio-transformer. Calculate audio transformer turns ratio for impedance matching between source and load, plus secondary voltage and current.

Inputs

Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.

Inputs of audio-transformer
Name	Unit	Range	Default	Description
primaryImpedancenumber	Ω	at least 1	600	Primary Impedance
secondaryImpedancenumber	Ω	at least 1	8	Secondary Impedance
primaryVoltagenumber	V	at least 0	1	Primary Voltage (RMS)
primaryCurrentnumber	A	at least 0	0.001	Primary Current (RMS)

Outputs

Returned in values, by key. A value that is unbounded or undefined is null.

Outputs of audio-transformer
Field	Unit	Description
turnsRatioheadline	:1	Turns Ratio (n)
secondaryVoltage	V	Secondary Voltage
secondaryCurrent	A	Secondary Current
powerTransferred	W	Power Transferred

Calling it

Calculate: one call, the request and response in full, and its errors.
Batch: this calculator with others, or a sweep, in one request.
Solve for a target: the value of one input that brings an output to a target.

curl -X POST https://rftools.io/api/py/v1/calculate \
  -H "X-API-Key: $RFTOOLS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "audio-transformer",
    "inputs": {
      "primaryImpedance": 600,
      "secondaryImpedance": 8,
      "primaryVoltage": 1,
      "primaryCurrent": 0.001
    }
  }'

import rftools

client = rftools.Client()  # reads RFTOOLS_API_KEY, or the key `rftools login` saved

result = client.calculate("audio-transformer", {
    "primaryImpedance": 600,
    "secondaryImpedance": 8,
    "primaryVoltage": 1,
    "primaryCurrent": 0.001,
})
print(result.values)
print(result.warnings, result.provenance.formula_ref)

const response = await fetch("https://rftools.io/api/py/v1/calculate", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.RFTOOLS_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "slug": "audio-transformer",
    "inputs": {
      "primaryImpedance": 600,
      "secondaryImpedance": 8,
      "primaryVoltage": 1,
      "primaryCurrent": 0.001
    }
  }),
});
console.log(response.status, await response.json());

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	body := []byte(`{
	  "slug": "audio-transformer",
	  "inputs": {
	    "primaryImpedance": 600,
	    "secondaryImpedance": 8,
	    "primaryVoltage": 1,
	    "primaryCurrent": 0.001
	  }
	}`)
	req, err := http.NewRequest("POST", "https://rftools.io/api/py/v1/calculate", bytes.NewReader(body))
	if err != nil {
		panic(err)
	}
	req.Header.Set("X-API-Key", os.Getenv("RFTOOLS_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}

application/json

{
  "slug": "audio-transformer",
  "values": {
    "turnsRatio": 8.660254037844387,
    "secondaryVoltage": 0.11547005383792514,
    "secondaryCurrent": 0.008660254037844388,
    "powerTransferred": 0.001
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:audio-transformer",
    "version": "api@3f2c1a9b04de",
    "formulaRef": null,
    "assumptions": [],
    "validRange": {
      "status": "inside",
      "bounds": {
        "primaryImpedance": {
          "min": 1,
          "max": null,
          "unit": "Ω"
        },
        "secondaryImpedance": {
          "min": 1,
          "max": null,
          "unit": "Ω"
        },
        "primaryVoltage": {
          "min": 0,
          "max": null,
          "unit": "V"
        },
        "primaryCurrent": {
          "min": 0,
          "max": null,
          "unit": "A"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "primaryImpedance": 600,
      "secondaryImpedance": 8,
      "primaryVoltage": 1,
      "primaryCurrent": 0.001
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "primaryImpedance"
      ],
      "msg": "Input should be a valid number, unable to parse string as a number",
      "input": "abc"
    }
  ]
}

An input sent as text. Nothing was counted.

{
  "detail": "More than 120 requests in 60 seconds from this address.",
  "errorKind": "rate_limited",
  "limit": 120,
  "windowSeconds": 60,
  "upgradeUrl": "https://rftools.io/pricing/"
}

Too many requests in a minute, with Retry-After.

Same inputs on the calculator pageAudio Transformer Turns Ratio, at these values