
Entries found for search: impedancematching
impedancematching : If the absolute maximum power is to be transferred from a source to a load, the impedances must match exactly. The source impedance output, the cable impedance, and the load impedance input have to be equal. This is called a matched circuit. However, when a circuit is matched, the voltage swing is reduced 6dB, lowering the best possible S/N ratio by that amount. Because of lownoise preamplifier circuits, there is a better audio tradeoff of power transfer for a larger voltage swing. Therefore, the idea that circuits should be impedancematched is fallacious, and instead modern audio equipment should simply be connected via balanced input and output lines. Systems that use high impedance mics are limited to cable lengths of around 10’ or so, but there is no reason to worry about the actual impedance value; it is either high or low. See bridging circuit.


