The inverting summing amplifier using an op-amp outputs a voltage equal to the sum of the voltages it has in its inputs. The explanation is based on an adder of three inputs but applies to an adder of any number of inputs

A window comparator lets you know if a signal is within or outside a previously defined acceptable voltage limit.

How to find the voltage gain (formula) in a non-inverting Op. Amp. How to find the Input impedance (Zi) and output impedance (Zo) of a non-inverting operational amplifier.

An op-amp can work as a comparator (voltage comparator) when the differential gain in the open loop is high and the speed is not a critical factor

A buffer has an output that is exactly like the input. This feature is very useful for solving impedance matching problems.

Op Amp Open Loop Gain – The open loop gain of the operational amplifier is given when there is no feedback path between the output and either input

Method #1: Voltage divider using two resistors. Method #2: Voltage divider using two Zener diodes.