Impedence

Just look at it as AC resistance!

A coil of nice thick wire will have virtually no (DC) resistance.

But it will have an impedance, e.g. a resistance to the flow of AC current, this is beacuse the AC will try and set up an alernating elecro magnetic field. Like just about everything in nature this field will tend to oppose the force that caused it.

In this example the impedance is inductive , you can also have capacitive impedance (DC won't go through a capacitor, but AC will, so again it's like AC resistance)

Impedance matching is basically about getting maximum power transfer from one circuit to another, or an efficient power transfer.

Look upon it as a flow of water! If you connect a 2inch diameter pipe to a 1/4" pipe you will not get maximum flow, you may also get pressure pulses reflected back down the pipe...this is a missmatch of diameter/ resistance/ impedance, call it what you will.

Hope this is helpful and simple.

I am the typical electronic layman.

impedence is the apparent resistance to AC.

A mismatch in impedance may result in the supply circuit delivering to much current and damage the electronics or cause disturbance (when moving out of the normal range of the amplifier. )

above description is right.

Impedence is a behaviour of resistance ac. It can dissipate only workless power, it dont waste useful power( if not include pure resistance).

match means the load can be acquired 50% maximum power from power. mismatch will get less this number.

besides, mismatch will cause many other odd phenomena, like short, open circuit etc. even if its not real short or oopen circuit.

Hi,

You know, I guess what resistance is, so we will take it from there:

Think of a tube with water flowing in it. The resistance (or lack of it,) to flow, is the impedance.Too much water a pressure is exerted on the tube's wall this pressure mean loss of energy, Right? Too little flow means turbulent flow, again loss of energy.

Now assume that we have to connect another tube to the one we have, but this time it is of a different diameter. The connection between the 2 tubes will cause a mismatch, or a match. Mismatch occurring when the flow in the new tube will be too much or too little. In both cases there is a loss of energy. Means we have a mis-match. If we will connect the 2 tubes through an iris for example to control the flow in such a way that the flow through new tube is smooth, no extra pressure or turbulent flow, we now have matched flow. and the iris a a the matching transformer.

Hope it helps.

Impedance= is the resistance to the flow of AC, (alternating current) in a circuit. and it is measured by OHMS (Ω), just like DC resistance.

Wangito

Impedance is a conductors Resistance to AC current flow.

it its due to inherent properties of the conductor. Many factors make up the impedance. Like the force necessary to dislodge an electron from its atom to the effects of the collapse of the magnet field which creates reverse current in the conductor. All of these are defined as one the impedance.

Impedance mismatch means that maximum power transfer will not be achieved.

To give an example, a typical television coaxial cable has 75 ohms impedance, and a typical television twin-lead has a 300 ohm impedance.

Although you can connect the 300 ohm twin-lead to a TV's 75 ohm coax input, you will not wind up with maximum power transfer. You do get maximum power transfer when impedances are matched.

There is a device, using the same example as above, called a balun (contraction of balanced to unbalanced) which is used to transform the 300 ohm, balanced line to a 75 ohm, unbalanced line. There is a slight amount of power loss in the balun, but it provides a larger signal than a direct connection of a 300 ohm line to a 75 ohm input.

Same can be said for driving an 8 ohm speaker with a 4 ohm output amplifier. You don't get maximum power transfer.