Op-amp Summing Amplifier

[Patrick Chung]

Good feature of op-amp summing amplifier is that there is direct current path provided from every input to the output. For that reasons input voltage sources don't need to have current sink capability.
Good feature of op-amp non inverting summing amplifier is that output voltage is proportional with the sum of the input signals, and with the same sign. Bad feature is that there is no direct current path from the inputs to the output, so input voltage sources must have sinking current capability.

Read more:

http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html

and also simulate:

http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php
http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php