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Using impedance matching or power matching you make the output impedance of a source equalto the input impedance of the load to which it is ultimately connected. T- and H-pads are used in radiofrequency (RF) circuits to attenuate a signal (damping). It is applied where maximum energy (power) is transferred between a source and a load. Then Z_{source} = Z_{load}.But in sound recording (audio), public address, and HiFi only impedance bridging is used with:
Z_{source} << Z_{load} or Z or _{S} << Z_{L}Z_{out} << Z_{in}The output impedance of the source is always much smaller than the input impedance of the load. In this case never try to calculate and use T- and H-pads circuits - better use voltage dividers instead. asymmetric symmetric Historical reasons show impedance values especially of 50 ohms, 200 ohms, or 600 ohms. Voltage Divider Calculator No. 1Entering three or four values calculate the others. The value of Z_{load} can be entered additionally,otherwise it uses automatically a 1 megohm load - unloaded open circuit. Use the left mouse button - click at a free space. |

*V*_{unloaded} means *V*_{out} without *Z*_{L}. If wanted, Z_{source} of the generator can be added to *Z*_{1}.

A negative solution means damping (loss) - positive solution means amplification (gain).

Voltage damping:

Output voltage:

Parallel resistance:

See also: **Calculation of damping
Impedance bridging or Voltage bridging Zout < Zin**

Unloaded voltage dividerRule of thumb: The voltages are proportional to the resistances.Formulas for the unloaded voltage divider: |

Calculator: Unloaded or open circuit voltage divider (potentiometer) |

**Voltage Divider Calculator No. 2**

This calculator, given any three or four of the five possible values, will
give the results for the remaining one. The Z_{L} value is optional, if not supplied, thecalculator uses 1 Megohm. Usefull if you need to enter V_{out}.Fill in any three or four fields in the form below, then click the "calculate" button. The remaining field will be calculated, and the results displayed. If you make a new calculation, use always the "reset" button to clear all the boxes. . Z = R |

To compute Input Voltage enter Z_{1}, Output Voltage, and Z_{2} and then click the calculate button.To compute Z_{1} enter Input Voltage, Output Voltage, and Z_{2} and then click the calculate button.To compute Z_{2} enter Input Voltage, Output Voltage, and Z_{1} and then click the calculate button.To compute Output Voltage enter Input Voltage, Z_{1} and Z_{2} and then click the calculate button.If wanted, Z _{source} of the generator can be added to Z_{1}. |

**Voltage division ratio α** = Ratio (Output Voltage to Input Voltage) =

dB (level) = 20 × log

Interconnection of two audio units - voltage bridging Z_{out} < Z_{in}Calculation of the damping of impedance bridging orimpedance matching an interface connecting Z _{out} and Z_{in} |

**Voltage divider (potentiometer) with different control characteristics**

**Figure: © Detlef Mietke − ****http://www.elektroniktutor.de/analog/u_teiler.html**

Interconnection of two audio units equals a circuit of a voltage divider − *Z*2 << *Z*1.

**Attention**: The numbering of the impedances is inversely to a voltage divider.

**A panpot is made of two voltage dividers:**

Calculator: Unloaded or open circuit voltage divider (potentiometer) |

In sound engineering there is no Impedance matching or Power matching.In audio we use only (high) Impedance bridging or Voltage bridging. |

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