Olin Lathrop wrote:

> yamanoor sairam wrote:
>> However, I tried to understand the concept of offset voltage in an
>> opamp from the link below:
> 
> First you have to understand how a ideal opamp works.  It takes the
> voltage on the + input minus the voltage on the - input, then
> multiplies that by a large number (the gain).  Often you consider the
> gain of a ideal opamp to be infinite.  You get useful linear results
> with this by using feedback.

Rather than working with the mental image of an infinite gain, I found
it quite useful in my early days to think of the opamp as a device that
sets its output so that both inputs are equal. This image has its
limitations, but it works well for circuits that don't run into
saturation and are mostly DC. It helped me a great deal understanding
the different circuits. (This still works when adding offset voltage and
current.)

Gerhard
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