Documentation sections

Hall Effect Sensor Calculator

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

Slug hall-effect-sensor. Calculate Hall voltage V_H = R_H·I·B/t, carrier density, and sensitivity for Hall effect sensors. Covers magnetic field measurement, current sensing, and position detection applications.

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 hall-effect-sensor
Name	Unit	Range	Default	Description
currentnumber	mA	0.001 … 1000	100	Control current flowing through the Hall element
Bfieldnumber	mT	at least 0.001	100	Applied magnetic field perpendicular to current flow
thicknessnumber	mm	at least 0.001	0.5	Thickness of the Hall element in the direction of magnetic field
carrierDensitynumber	×10²³/m³	at least 0.001	8.5	Charge carrier density in units of 10²³ per m³: copper 8.5×10⁵ (8.5×10²⁸/m³), InSb about 0.2 (2×10²²/m³ at room temperature), intrinsic silicon 1.5×10⁻⁷ (1.5×10¹⁶/m³)
frontGainnumber	V/V	0.01 … 1000000	4000	The gain between the Hall element and the ADC. A gain of 4000 brings the default element's 0.73 mV at 500 mT to about 2.9 V.
adcRefnumber	V	0.1 … 50	3.3	The ADC full scale
adcBitsnumber	bit	1 … 24	12	ADC resolution in bits

Outputs

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

Outputs of hall-effect-sensor
Field	Unit	Description
hallVoltageheadline	mV	Developed Hall voltage across the element
hallCoefficient	m³/C	Hall coefficient R_H = 1/(n·e)
sensitivity	mV/mT	Hall sensor sensitivity: output mV per mT of applied field
amplifiedVoltage	V	The Hall voltage times the amplifier gain
adcCode	none	The code an ideal ADC reads: floor(V_amp / V_ref × 2^N)
resolution	mT/LSB	The field one ADC step spans

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": "hall-effect-sensor",
    "inputs": {
      "current": 100,
      "Bfield": 100,
      "thickness": 0.5,
      "carrierDensity": 8.5,
      "frontGain": 4000,
      "adcRef": 3.3,
      "adcBits": 12
    }
  }'

import rftools

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

result = client.calculate("hall-effect-sensor", {
    "current": 100,
    "Bfield": 100,
    "thickness": 0.5,
    "carrierDensity": 8.5,
    "frontGain": 4000,
    "adcRef": 3.3,
    "adcBits": 12,
})
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": "hall-effect-sensor",
    "inputs": {
      "current": 100,
      "Bfield": 100,
      "thickness": 0.5,
      "carrierDensity": 8.5,
      "frontGain": 4000,
      "adcRef": 3.3,
      "adcBits": 12
    }
  }),
});
console.log(response.status, await response.json());

package main

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

func main() {
	body := []byte(`{
	  "slug": "hall-effect-sensor",
	  "inputs": {
	    "current": 100,
	    "Bfield": 100,
	    "thickness": 0.5,
	    "carrierDensity": 8.5,
	    "frontGain": 4000,
	    "adcRef": 3.3,
	    "adcBits": 12
	  }
	}`)
	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": "hall-effect-sensor",
  "values": {
    "hallVoltage": 0.14685903704613562,
    "hallCoefficient": 0.000007342951852306781,
    "sensitivity": 0.0014685903704613561,
    "amplifiedVoltage": 0.5874361481845425,
    "adcCode": 729,
    "resolution": 0.13714921442779537
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:hall-effect-sensor",
    "version": "api@3f2c1a9b04de",
    "formulaRef": null,
    "assumptions": [],
    "validRange": {
      "status": "inside",
      "bounds": {
        "current": {
          "min": 0.001,
          "max": 1000,
          "unit": "mA"
        },
        "Bfield": {
          "min": 0.001,
          "max": null,
          "unit": "mT"
        },
        "thickness": {
          "min": 0.001,
          "max": null,
          "unit": "mm"
        },
        "carrierDensity": {
          "min": 0.001,
          "max": null,
          "unit": "×10²³/m³"
        },
        "frontGain": {
          "min": 0.01,
          "max": 1000000,
          "unit": "V/V"
        },
        "adcRef": {
          "min": 0.1,
          "max": 50,
          "unit": "V"
        },
        "adcBits": {
          "min": 1,
          "max": 24,
          "unit": "bit"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "current": 100,
      "Bfield": 100,
      "thickness": 0.5,
      "carrierDensity": 8.5,
      "frontGain": 4000,
      "adcRef": 3.3,
      "adcBits": 12
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "current"
      ],
      "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 pageHall Effect Sensor Calculator, at these values