# Operation Amplifier

These devices follow some rules

 - the output attempts to do whatever is necessary to make
   the voltage difference between the inputs zero
 - the inputs draw no current

## Links

 - [Op Amps for everyone](https://focus.ti.com/lit/an/slod006b/slod006b.pdf)
 - [Using Op Amps as Comparators](http://www.analog.com/media/en/technical-documentation/application-notes/AN-849.pdf)