{
  "id": "bridged-tee-attenuator",
  "slug": "bridged-tee-attenuator-calculator",
  "url": "https://electronics.tools/tools/bridged-tee-attenuator-calculator/",
  "name": "Bridged-Tee Attenuator Calculator",
  "group": "rf",
  "summary": "A 10 dB bridged-tee for 50 Ω keeps the arms at 50 Ω; Rbridge = 108.1 Ω, Rshunt = 23.12 Ω.",
  "formulas": [
    {
      "id": "k",
      "label": "Voltage ratio",
      "plain": "K = 10^(A/20)",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"K = 10^(A/20)\"><mrow><mi>K</mi><mo>=</mo><msup><mn>10</mn><mrow><mi>A</mi><mo>/</mo><mn>20</mn></mrow></msup></mrow></math>",
      "symbols": [
        "K",
        "A"
      ],
      "sources": [
        "itt"
      ]
    },
    {
      "id": "parasitics",
      "label": "High attenuation",
      "plain": "A above 60 dB: parasitics dominate; values are theoretical",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"A above 60 dB: parasitics dominate; values are theoretical\"><mrow><mi>A</mi><mo>&gt;</mo><mn>60</mn><mspace width=\"0.167em\"></mspace><mtext>dB</mtext></mrow></math>",
      "symbols": [
        "A"
      ],
      "sources": [
        "itt"
      ]
    },
    {
      "id": "e96",
      "label": "Preferred values",
      "plain": "E96 nearest preferred values",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"E96 nearest preferred values\"><mrow><msub><mi>R</mi><mtext>E96</mtext></msub><mo>=</mo><mtext>nearest</mtext><mspace width=\"0.167em\"></mspace><mi>E</mi><mn>96</mn><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math>",
      "symbols": [
        "RbrE96",
        "RshE96"
      ],
      "sources": [
        "itt"
      ]
    },
    {
      "id": "net",
      "label": "Bridged-Tee Attenuator Calculator",
      "plain": "arms = Z0; Rbr = Z0(K−1); Rsh = Z0/(K−1)",
      "mathml": "<math display=\"block\" xmlns=\"http://www.w3.org/1998/Math/MathML\" aria-label=\"arms = Z0; Rbr = Z0(K−1); Rsh = Z0/(K−1)\"><mrow><msub><mi>R</mi><mtext>arm</mtext></msub><mo>=</mo><msub><mi>Z</mi><mn>0</mn></msub><mo>,</mo><mspace width=\"0.278em\"></mspace><msub><mi>R</mi><mtext>br</mtext></msub><mo>=</mo><msub><mi>Z</mi><mn>0</mn></msub><mrow><mo>(</mo><mrow><mi>K</mi><mo>-</mo><mn>1</mn></mrow><mo>)</mo></mrow><mo>,</mo><mspace width=\"0.278em\"></mspace><msub><mi>R</mi><mtext>sh</mtext></msub><mo>=</mo><msub><mi>Z</mi><mn>0</mn></msub><mo>/</mo><mrow><mo>(</mo><mrow><mi>K</mi><mo>-</mo><mn>1</mn></mrow><mo>)</mo></mrow></mrow></math>",
      "symbols": [
        "Rarm",
        "Z0",
        "Rbr",
        "K",
        "Rsh"
      ],
      "sources": [
        "itt"
      ]
    }
  ],
  "variables": [
    {
      "symbol": "A",
      "name": "Attenuation",
      "unit": "dB",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0,
        "note": "A must be > 0"
      },
      "default": 10,
      "urlParam": "a"
    },
    {
      "symbol": "Z0",
      "name": "Characteristic impedance",
      "unit": "Ω",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0
      },
      "default": 50,
      "urlParam": "z0"
    },
    {
      "symbol": "Pin",
      "name": "Input power (optional)",
      "unit": "W",
      "role": "input",
      "precision": {
        "sig": 4
      },
      "range": {
        "min": 0
      },
      "default": "",
      "urlParam": "pin"
    },
    {
      "symbol": "K",
      "name": "Voltage ratio",
      "unit": "1",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Zin",
      "name": "Input impedance",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "AdB",
      "name": "Ideal attenuation",
      "unit": "dB",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "AE96",
      "name": "E96 attenuation",
      "unit": "dB",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "RL",
      "name": "Return loss",
      "unit": "dB",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Rarm",
      "name": "Arm resistor",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Rbr",
      "name": "Bridge resistor",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Rsh",
      "name": "Shunt resistor",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "RbrE96",
      "name": "Bridge E96",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "RshE96",
      "name": "Shunt E96",
      "unit": "Ω",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Pbr",
      "name": "Bridge dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "ParmIn",
      "name": "Input arm dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "ParmOut",
      "name": "Output arm dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Psh",
      "name": "Shunt dissipation",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    },
    {
      "symbol": "Pload",
      "name": "Load power",
      "unit": "W",
      "role": "output",
      "precision": {
        "sig": 4
      }
    }
  ],
  "examples": [
    {
      "id": "10db-50",
      "title": "10 dB / 50 Ω",
      "input": [
        {
          "symbol": "A",
          "value": 10,
          "unit": "dB",
          "display": "10 dB"
        },
        {
          "symbol": "Z0",
          "value": 50,
          "unit": "Ω",
          "display": "50 Ω"
        }
      ],
      "output": [
        {
          "symbol": "K",
          "value": 3.1622776601683795,
          "unit": "1",
          "display": "3.162"
        },
        {
          "symbol": "AdB",
          "value": 10,
          "unit": "dB",
          "display": "10 dB"
        },
        {
          "symbol": "AE96",
          "value": 9.952848677633922,
          "unit": "dB",
          "display": "9.953 dB"
        },
        {
          "symbol": "Zin",
          "value": 50,
          "unit": "Ω",
          "display": "50 Ω"
        },
        {
          "symbol": "Rarm",
          "value": 50,
          "unit": "Ω",
          "display": "50 Ω"
        },
        {
          "symbol": "Rbr",
          "value": 108.11388300841898,
          "unit": "Ω",
          "display": "108.1 Ω"
        },
        {
          "symbol": "Rsh",
          "value": 23.123764778713216,
          "unit": "Ω",
          "display": "23.12 Ω"
        }
      ],
      "computedBy": "compute"
    },
    {
      "id": "6db-50",
      "title": "6 dB / 50 Ω",
      "input": [
        {
          "symbol": "A",
          "value": 6,
          "unit": "dB",
          "display": "6 dB"
        },
        {
          "symbol": "Z0",
          "value": 50,
          "unit": "Ω",
          "display": "50 Ω"
        }
      ],
      "output": [
        {
          "symbol": "AdB",
          "value": 6,
          "unit": "dB",
          "display": "6 dB"
        },
        {
          "symbol": "K",
          "value": 1.9952623149688795,
          "unit": "1",
          "display": "1.995"
        }
      ],
      "computedBy": "compute"
    }
  ],
  "sources": [
    {
      "title": "Attenuator (electronics)",
      "url": "https://en.wikipedia.org/wiki/Attenuator_(electronics)",
      "retrieved": "2026-11-02"
    }
  ],
  "datePublished": "2026-11-02T00:00:00+08:00",
  "dateModified": "2026-11-02T00:00:00+08:00",
  "author": {
    "name": "Jasper",
    "url": "https://electronics.tools/about/#jasper"
  },
  "relatedTools": [
    "https://electronics.tools/tools/pi-attenuator-calculator/",
    "https://electronics.tools/tools/tee-attenuator-calculator/",
    "https://electronics.tools/tools/reflection-attenuator-calculator/"
  ]
}