what is the reason behind op-amp symbol?

[1189raji]

Hi friends,
Can anyone help me out of this question.Why op-amp symbol is triangle in shape.



regards,
rajeshwari
1189raji@gmail.com

 

[LvW]

Hi friends,
Can anyone help me out of this question.Why op-amp symbol is triangle in shape.

Why? Perhaps to avoid a mixing up with other elements (resistors, capaciotrs)? Not a good answer?
I suppose, somebody has recommended it several years ago.
By the way - do you know that there are two different symbols for a resistor?

 

[crutschow]

It's rather arbitrary but Op amps typically have two active inputs and one output and a triangle would seem to readily represent that. Do you have a better shape in mind?

 

[godfreyl]

I can't help imagining Bob Widlar being too drunk to draw a square one day.:grin:

Maybe it started like that, then somebody figured what he'd scribbled was actually a more sensible symbol anyway, and a new convention was born.

R.I.P. Bob

 

[chuckey]

From Wkipedia :- "1941: A vacuum tube op-amp. An op-amp, defined as a general-purpose, DC-coupled, high gain, inverting feedback amplifier, is first found in U.S. Patent 2,401,779 "Summing Amplifier" filed by Karl D. Swartzel Jr. of Bell Labs in 1941. This design used three vacuum tubes to achieve a gain of 90 dB and operated on voltage rails of ±350 V. It had a single inverting input rather than differential inverting and non-inverting inputs, as are common in today's op-amps. Throughout World War II, Swartzel's design proved its value by being liberally used in the M9 artillery director designed at Bell Labs. This artillery director worked with the SCR584 radar system to achieve extraordinary hit rates (near 90%) that would not have been possible otherwise.[11]" Nothing new under the sun!
Frank

 

[1189raji]

Why? Perhaps to avoid a mixing up with other elements (resistors, capaciotrs)? Not a good answer?
I suppose, somebody has recommended it several years ago.
By the way - do you know that there are two different symbols for a resistor?

Hi,
Thank you for your response but still i couldn't able to get why the symbol is so? i think there will be some reason behind it??

 

[rusty81]

Is not for the fact that has 2 inputs and 1 output, LNA (Low Noise Amplifier) has 1 input 1 output and on schematics have the same triangular shape.

In my opinion we must look at the triangle like an arrow, telling us that there is a power transfer from left, rising to right.

 

[Ow@i$]

Well guys I think better should just stick with what it does than why & what it looks like, hopefully the creator must have thought some "logical" reason for it, or Else brace yourself for "Creative Reasons" being forwarded by everyone

 

[Resistor123]

The Op-amp symbol is triangular to show an arrow or direction of power transfer (input to the output). Op-amp transfers the power from the input terminal to the output terminal.

 

[Analog Ground]

Your question about the origins of the op amp symbol is an interesting one.The first commercial op amp used vacuum tubes and was available in 1952. Data sheets from that time use the familiar triangle symbol. BTW, there is an alternate version of the symbol which has an outwardly curving line on the left side with the + and - inputs. To me, the next step is to understand that operational amplifiers originated in the days of analog computers. Search "analog computing symbols" and you see vintage documents with symbols for amplification, summing, integration, etc. which appear as variations on the triangle we use today. So, my theory is the symbol originates from the days of analog computing. Let me pose another question. Why are they called "operational" amplifiers?

 

[rusty81]

Why are they called "operational" amplifiers?

Because in the early days of computing they were used for analogic algebrical operation, like sum, subtracions, and from these products (iterative sum) and division (iterative sum and subtration).
In an analog calculator data was represented by voltages, and from this assumption many operation can be made on an analogic world

 

[zywts]

do know know may be get it from inverter?