# Ideal Voltage Amp

Discussion in 'Homework Help' started by James4553, Mar 5, 2009.

1. ### James4553 Thread Starter Active Member

Jun 7, 2008
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Could someone please explain to me why an ideal voltage amp would (ideally) have the input impedance as infinite??

2. ### beenthere Retired Moderator

Apr 20, 2004
15,815
283
Infinite input impedance means no power used to drive it's input. No distortion effects on the input. Basically, think of every possible loading effect on a signal, and why the ideal op amp will not exhibit any of them.

3. ### GirishC Active Member

Jan 23, 2009
58
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For voltage amplifier, if you have input impedance very high (infinite) compared with input series resistance/ impedance, the input voltage comes across high values and that's the requirement for voltage amplifier. In case of current amplifier its other way round and its true even using opamp.

4. ### mik3 Senior Member

Feb 4, 2008
4,846
63
Because an infinite input impedance would be desired if possible. This is because no current would flow into (or out of) the input of the amplifier, no voltage would be dropped across the internal impedance of the signal source and the whole voltage provided by the signal source would appear at the amplifier's input and thus a higher output voltage would be got.

Still confused!