Calculation of the damping bridging circuit devices damping factor power matching or impedance matching - sengpielaudio Checker
 
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• Calculation of Damping •

Bridging (voltage) or  matching (power)
of an interface connecting Zout and Zin impedance

That means level damping compared to the open circuit case.

Calculation of the damping factor DF

Zout is the source impedance Z2 (internal impedance) or the output impedance of the first audio device
and Zin is the load impedance Z1 (external impedance) or the input impedance of the following device.
Voltage bridging: Z1 >> Z2 or Zin >> Zout or Zload >> Zsource or Z1 >> Z2 in the audio world
Power matching: Z1 = Z2 or Zin = Zout or Zload = Zsource or Z1 = Z2 in the radio frequency world

Bridging Z2 and Z1 - sengpielaudio

Interconnection of two audio units equals a circuit of a voltage divider − Z2 << Z1.

Interface - sengpielaudio

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

Voltage divider - changed numbers

 Source impedance Z2 =   ohms
Load impedance Z1 =   ohms
     
↓
     
Level damping Δ L =   dB
Damping factor DF =   = Z1 / Z2 = Zin / Zout
Even in the sound studio the voltage bridging Z1 > Z2 will bring a level drop, depending
on the difference between Z1 (Zin) and Z2 (Zout) with the bridging factor:  Bridging factor - sengpielaudio.
Calculation of level damping (bridging):  Bridging Formula - sengpielaudio in dB.
Calculation of the damping factor:  Damping Formula - sengpielaudio.
Bridging factor is not damping factor.

Different names of the two impedances Z1 and Z2

Different names of the impedances - sengpielaudio

If the load impedance is 10 times or more the source impedance, this
is called a "bridging" impedance.
It results in maximum VOLTAGE transfer from the source to the load.

If the load impedance equals the source impedance, this is called
a "matching" impedance.
It results in maximum POWER transfer from the source to the load.

In the audio world we are happy with the maximum voltage transfer.
But we are often confronted with storytellers teaching us the myth of
power matching. Never believe that.

The two impedances Z1 and Z2 at one device

Impedances of an amplifier - sengpielaudio

Calculations: voltage divider (potentiometer)
damping pad - loaded and open circuit (unloaded)

Voltage Bridging - Interconnection of two units - Signal Loss

The damping factor is usually given as numerical value, but also in decibels.

Enter a value in the left or right box, then press the TAB bar or make
a mouse click at an empty space at the side, to get the solution.
The calculator works in both directions of the ↔ sign.

Damping factor DF as number: 
Ra/Ri		  ↔  Damping factor as dB value:
dB
Formula DF   Formula DF in dB
DF = 10 ≡ 20 dB                DF = 100 ≡ 40 dB

Calculation of the damping factor.

How do I calculate the damping factor DF for example, at 1 kHz, if neither the
impedance of the source Z2 nor the impedance of the load Z1 is known?
Allow the source to send out of a 1 kHz sine tone and measure the resulting voltage
V0 at the output without any load. Then measure at this point the voltage VL, when
the load is applied. The damping factor is:

DF = V0 / (V0 − VL)

(V0 − VL) is the voltage drop by the connected load.


Power matching or impedance matching

Power matching is a connection of the electronics design practice for telephone lines
and radio frequencies of setting the input impedance (ZL) of an electrical load equal
to the fixed output impedance (ZS) of the signal source to which it is ultimately
connected, usually in order to maximize the power transfer and minimize reflections
from the load. ZL = ZS.
This includes all digital device connections (interface).

The other configuration, especially for audio and sound recording is an
impedance bridging, voltage bridging, or simply bridging is a connection which
maximizes the transfer of a voltage signal to the load. ZL >> ZS.

Quite often this matching is erroneously demanded connecting the power amplifier
to the loudspeaker. Where does this wrong "knowledge" come from?

Aha!
Notice:
There are no 4 ohm amplifiers.
There are really no 8 ohm amplifiers
for the 4 ohm or 8 ohm loudspeakers.

We got speaker impedance bridging. There is no speaker impedance matching.

That is an ineradicable myth. The output impedance of the amplifier is always a
tenth or a hundredth of the value of the loudspeaker impedance.
The value of the output impedance of the amplifier Zsource is always hidden in
the damping factor DF and can easily be calulated:
Zsource = Zload / DF.     Zload is the impedance of the loudspeaker.
The cable resistance (impedance) is a part of the output impedance of the
amplifier. Because of the high voltage of the source, cable screening (shielding)
is here not necessary.

The typical continuous query in the forums: "Can I use 4 ohm speakers to a
6 ohms amplifier?" (See reply under "Notice".)

These issues show that there must be storytellers underway. How can we get
rid of the nonsense of 2 to 16 ohms amplifiers?
The output impedance of an amplifier Zout is always smaller than 0.5 Ohm.
Zout << Zin.

Amateurs are happy to speak of an 8 ohm amplifier, if they think that the amplifier
output should be connected to "8 ohm speakers". Dealers use exactly these
unclear expressions. In reality, the speaker impedance curve of a loudspeaker
is never a stright line.

Impedance bridging

Impedance bridging, voltage bridging, or simply bridging connection is a connection of the electronics design practice, especially for audio and sound
recording, which maximizes the transfer of a voltage signal to the load.
ZL >> ZS. This really also applies to loudspeakers.

The other configuration especially for telephone lines antennas, and radio
frequencies is a power matching (impedance matching) connection, which
maximizes power delivered to the load. ZL = ZS. This includes all digital device
connections (interfaces).

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