Low and High impedance terminology

[zalzon]

Keep reading this has a 'low impedence' and that has a 'high
impedance'. What really does it mean?

Does a high input impedance device not draw much current when attached
to a circuit? What is an example of a high impedance load?

How about low impedance. What are some examples of low impedance
loads?

I'm thinking of input and output impedance in terms of resistance to
the flow of current. Is this right? The greater the impedance,
probably the more current is needed to drive it.

 

[Kevin Aylward]

zalzon wrote:

Keep reading this has a 'low impedence' and that has a 'high
impedance'. What really does it mean?

Does a high input impedance device not draw much current when attached
to a circuit? What is an example of a high impedance load?

Guitar amplifier inputs.

How about low impedance. What are some examples of low impedance
loads?

Amplifier outputs.

I'm thinking of input and output impedance in terms of resistance to
the flow of current. Is this right?

Yes.

The greater the impedance,

probably the more current is needed to drive it.

No, The more voltage is needed to drive it for a given current. Current
is a flow of charge.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

[JeffM]

...high input impedance
..low impedance
Kevin Aylward

also
high impedance --> more susceptible to noise
(lower currents == more susceptible to noise currents)

low impedance --> less susceptible to noise
(higher currents == less susceptible to noise currents)