Yes, yes they are! The Operational Amplifiers (op-amps) are among the most widely used electronic devices in consumer, industrial, and scientific electronics. They were originally produced for mathematical operations (hence its name) but in fact they can be used for many many other purposes.
You know, back in the day, op-amps were constructed from vacuum tubes, meaning that they were poorly functional power hungry-devices that wouldn’t make it till these days if it wasn’t for one person, so if you ever have to thank anyone for pretty much everything you enjoy of modern day electronics (and probably for robots wiping out mankind) is this man: Robert Widlar
Bob Widlar was an electronic engineer in the 60s, he’s better known for being the designer of the first mass-produced op-amp IC in 1966 (among other cool stuff like the first voltage regulator IC) but also for his akward pranks and rabit ass way of life that are remembered in legends, myths and anecdotes, just like this one:
“On one occasion, when National Semiconductor tried to save money by cutting its landscaping expenses, Mr. Widlar brought a goat to work in his car to eat the grass in front of the company headquarters.”
At the age of 33, when he was wealthy enough on company stocks and already a "legendary chip designer", Widlar quit his job, left Sillicon Valley and hide somewhere in Mexico where he lived until his death in 1991.
So... how do they work?
In a very basic way, an op-amp is an electronic device with two inputs and one output.
The value of the output is the difference in voltage between the two inputs multiplied for a gain factor, the usual gain (in open loop) is very large, and I mean quite fucking huge (over 9000!)… that means that even a very small difference between the inputs (and I’m talking micro volts here) will result in amplifier saturation.
Amplifier Saturation: If higher voltage is applied to the pin V+, the output will corresponds to the source VS+, however, if the higher voltage is applied to the pin V- , the output will be VS-.
That should do the trick if what you want is a comparator circuit to, let’s say, “control the direction of a DC motor”. On the other hand, if you plan to build a death laser machine to destroy France you’ll need to control that gain somehow… a feedback into the circuit is the way to go.
Feedback enables the amplifier to keep the inputs at almost the same voltage, avoiding that evil saturation stuff. However, you got to be careful; shit comes in two flavors, positive feedback and negative feedback. Usually, negative feedback is the one you want to hang up with.
The previous image shows a non inverting amplifier.There are a lot of resistor/capacitor or even coil configurations for the op-amps depending on the application you need. If you're interested, you really should give a look to this article. I also recommend you this links if you want to dig deeper on the history and insides of an op-amp.
- http://www.national.com/rap/Story/widlar.html
- http://www.analog.com/library/analogdialogue/archives/39-05/web_chh_final.pdf
nice!
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