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shiva kumar
shiva kumar • Aug 10, 2008

Op Amps

HI
OP AMP IS AN HIGH GAIN DIFFERENTIAL AMPLIFIER BUT IDEALLY IT SHOULD NOT ACCEPT ANT CURRENT, WHAT ON EARTH THIS COULD MEAN ?
😒IF IT SHOULD NOT ACCEPT ANY CURRENT HOW CAN IT PROCESS I MEAN AMPLIFY THE SIGNAL
CAN ANY ONE EXPLAIN ME ABOUT VIRTUAL GROUND
prestonee
prestonee • Aug 11, 2008
The inputs are high impedence, meaning it will not have a current draw on the input (except for gate leakage for a mosfet design), of course the amplifier still has a powersupply that will have current draw.

BJT amplifiers arent my thing but the nature of a bjt allows current flow into its base, so im thinking these amplifiers will have input current draw depending on the resistor on the base.

Virtual ground term is used in AC analysis, in a typical 5 transistor amplifier, where you have a current souce that then connects to 2 input fets, this node would be a virtual ground because though there is a DC voltage on this node, it is constant and so at an AC standpoint it is basically ground ( 0 signal change). There are more academic definitions out that you can can wiki or look up in a text book, but basically virtual ground is when the voltage is purely DC, when performing an AC analysis.
shiva kumar
shiva kumar • Aug 12, 2008
thanx dude

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