OP-AMP
Operational amplifier
An analogue amplifier represented by inverting and non-inverting inputs, an output and its supply connections.
Schematic
IEC · ▷∞
IEC operational amplifier (rectangular form)
Rectangular IEC-style op-amp drawn as a box with an amplifier triangle and an infinity sign for very high gain.
In plain English
What does IEC operational amplifier (rectangular form) mean?
In IEC-style analogue element diagrams an operational amplifier is often drawn as a rectangle containing a small amplifier triangle and an infinity sign, meaning very high open-loop gain. Inverting and non-inverting inputs are marked with minus and plus signs at the input side.
A simple example
This form appears on European instrumentation and protection relay schematics, where analogue elements share the rectangular style used for logic. The surrounding feedback network defines what the circuit does, so the resistor and capacitor values must be read together with the element.
What the drawings help you do
The rectangular form gives no information about supply rails, offset, bandwidth or output swing. Those are device parameters, and the supply pins are often omitted from functional diagrams.
This particular reference
Rectangular IEC-style op-amp drawn as a box with an amplifier triangle and an infinity sign for very high gain. The triangular ANSI-style op-amp is the same device drawn without the rectangle.
- Normally open / normally closed
- The contact state in the normal condition defined for the drawing.
- Coil
- A wound conductor that can produce a magnetic field when energised.
- Signal
- Electrical information passed between devices, rather than necessarily the main power supply.
Read the source: IEC graphical symbols for diagrams · ADA4522-1 — operational amplification
IEC · Rectangular outline with amplifier triangle and infinity sign
IEC-style rectangular analogue element presentation; the IEC graphical symbols programme is cited for context only. Independent educational drawing; not certified IEC geometry or an IEC database identifier. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
Schematic · ▷∞
What it represents
In IEC-style analogue element diagrams an operational amplifier is often drawn as a rectangle containing a small amplifier triangle and an infinity sign, meaning very high open-loop gain. Inverting and non-inverting inputs are marked with minus and plus signs at the input side.
This form appears on European instrumentation and protection relay schematics, where analogue elements share the rectangular style used for logic. The surrounding feedback network defines what the circuit does, so the resistor and capacitor values must be read together with the element.
The rectangular form gives no information about supply rails, offset, bandwidth or output swing. Those are device parameters, and the supply pins are often omitted from functional diagrams.
How to read it
- Find the minus and plus inputs before reading the feedback network.
- Supply connections are often omitted.
Information to show or reference
- Mark inverting and non-inverting inputs.
- Show the feedback network with values.
- Note supply rails where they matter.
A distinction that matters
The triangular ANSI-style op-amp is the same device drawn without the rectangle.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
IEC graphical symbols for diagrams
IEC graphical symbols programme covering analogue elements; no geometry reproduced.
ADA4522-1 — operational amplification
Manufacturer operational amplifier documentation.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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