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previous: Ed Rembold Vetrans,which is most prefe... -- 5/18/2000 5:28 AM

Re: OPamp "summing" question

5/18/2000 2:54 PM
peter	Re: OPamp "summing" question there is a reason why the inverting input is used: the negative feedback connection works to put the (-) input at "virtual ground", so there is no leakage between input signals, and the impedance to ground for each signal is constant. If you sum at the (+) input the voltage at the input is driven up and down by the signals so the impedance seen by the signal sources varies.

5/18/2000 2:54 PM

peter

Re: OPamp "summing" question

there is a reason why the inverting input
is used: the negative feedback connection
works to put the (-) input at "virtual
ground", so there is no leakage between
input signals, and the impedance to
ground for each signal is constant.

If you sum at the (+) input the voltage at
the input is driven up and down by the signals
so the impedance seen by the signal sources varies.